Heads of state and government from NATO's 30 member states met in London, United Kingdom (UK), on December 3-4, 2019. NATO and U.S. officials highlighted the following key deliverables from the London Leaders' Meeting: Completion of a new Readiness Initiative, under which the alliance would have at its disposal 30 mechanized battalions, 30 air squadrons, and 30 naval combat vessels ready to use within 30 days. Declaration of space as a new operational domain for NATO and advances in combatting cyber and hybrid threats, including establishing new baseline requirements for telecommunications infrastructure. Increased defense spending by European allies and Canada. Renewed commitment to NATO's mission in Afghanistan and counterterrorism efforts in the Middle East and North Africa. Agreement to assess China's impact on NATO and transatlantic security. Initiation of a new "forward-looking reflection process â¦ to further strengthen NATO's political dimension including consultation." More broadly, NATO officials sought to highlight NATO's achievements and the importance of strong U.S.-European relations to these efforts. The United States was the driving proponent of NATO's creation in 1949 and has been the unquestioned leader of the alliance as it has evolved from a collective defense organization of 12 members focused on deterring the Soviet Union to a globally engaged security organization of 30 members. Successive U.S. Administrations have viewed U.S. leadership of NATO as a cornerstone of U.S. national security strategy that brings benefits ranging from peace and stability in Europe to the political and military support of 28 allies, including many of the world's most advanced militaries. The London meeting came at a tense time for NATO, however. Some European allies question the Trump Administration's commitment to NATO and have criticized the Administration for a perceived unilateral approach to foreign policy issues, including the October 2019 drawdown of U.S. forces from Syria. Many allies also have criticized fellow NATO member Turkey for its military operations in Syria and its acquisition of a Russian-made air defense system. NATO Secretary General Jens Stoltenberg acknowledges ongoing tensions within the alliance but stresses that continued transatlantic cooperation has enabled NATO to be more active today than it has been in decades. Trump Administration officials maintain that the United States remains committed to NATO, and in London, President Trump stressed that NATO "has a great purpose." U.S. officials also highlight the Administration's successful efforts in 2017 and 2018 to substantially increase funding for the U.S. force presence in Europe and note that Secretary General Stoltenberg has credited President Trump with playing a role in securing defense spending increases across the alliance in recent years. Critics of the Trump Administration's NATO policy maintain that renewed Russian aggression has been a key factor behind such increases. At the London meeting, NATO leaders stressed their commitment to advancing existing readiness and deterrence initiatives and to confronting emerging security challenges, including by declaring space as an operational domain for NATO. The allies also reinforced their commitment to NATO's ongoing mission in Afghanistan and other counterterrorism efforts and discussed the implications for NATO of China's growing investment in, and engagement with, Europe. In the five years since Russia occupied Crimea and invaded Eastern Ukraine, the United States has supported efforts to renew NATO's focus on territorial defense and deterring Russian aggression. Among other measures, NATO member states have deployed an Enhanced Forward Presence (EFP) totaling about 4,500 troops to the three Baltic States (Estonia, Latvia, and Lithuania) and Poland; increased military exercises and training activities in Central and Eastern Europe; and established new NATO command structures in six Central and Eastern European countries. In London, the allies announced progress on several new initiatives intended to enhance NATO's readiness to respond swiftly to an attack on a NATO member, including by reinforcing the aforementioned EFP battlegroups. A cornerstone of these efforts is full implementation by the end of 2019 of the so-called Four-Thirties Readiness Initiative, proposed by the United States in 2018, under which NATO would have 30 mechanized battalions, 30 air squadrons, and 30 naval combat vessels ready to use within 30 days. Although the allies have continued to support and contribute to NATO deterrence initiatives, some analysts question the effectiveness and sustainability of these efforts. For example, the authors of a February 2016 report by the RAND Corporation contend that "as presently postured, NATO cannot successfully defend the territory of its most exposed members." Some allies, including Poland and the Baltic States, have urged other NATO members to deploy more forces to the region to reinforce that alliance's deterrence posture. Other allies, including leaders in Western European countries such as Germany, Italy, and France, have stressed the importance of a dual-track approach to Russia that complements deterrence with dialogue. These allies contend that efforts to rebuild cooperative relations with Moscow should receive as much attention as efforts to deter Russia. Accordingly, these allies are reluctant to endorse permanently deploying troops in countries that joined NATO after the collapse of the Soviet Union due to concerns that this would violate the terms of the 1997 NATO-Russia Founding Act; in consideration of these terms, NATO's EFP has been referred to as "continuous" but rotational rather than "permanent." In London, the allies highlighted progress in responding to cyber and hybrid threats and formally declared space as a new operational domain for the alliance. Since naming cyber defense a core NATO competence in 2014, the alliance has adopted measures to protect NATO networks from cyberattacks and to assist member states in bolstering national cyber defense capabilities. NATO has made available Cyber Rapid Reaction Teams to help allies respond to cyberattacks, and in 2018 it announced plans to establish a new NATO Cyberspace Operations Center in Brussels. The new cyber center will focus on integrating allies' national cyber capabilities into NATO missions and operations. Although NATO member states maintain full ownership of these capabilitiesâas they do with other military capabilities deployed to NATO missionsâthe new operations center is tasked with incorporating cyber defense into all levels of NATO planning and operations. NATO also has sought to bolster capabilities to counter heightened hybrid warfare threats, including propaganda, deception, sabotage, and other nonmilitary tactics. NATO's focus has been on enhancing strategic communications, developing appropriate exercise scenarios, and strengthening coordination with the European Union (EU) to respond to hybrid threats. At their meeting in 2018, NATO leaders agreed to establish counter-hybrid support teams to provide tailored assistance to allies in preparing against and responding to hybrid activities. NATO deployed the first of these teams to Montenegro in November 2019. As discussed in more detail below (see " Assessing China's Impact on NATO and Transatlantic Security "), in London, NATO leaders endorsed new baseline requirements for allies with respect to the resilience of telecommunications infrastructure, including 5G systems. In London, NATO leaders formally declared space as an operational domain for NATO, alongside air, land, sea, and cyber. Secretary General Stoltenberg stated that the declaration reflects a consensus desire within NATO to strengthen defense and deterrence in all areas, including space, where NATO allies reportedly own about half of the approximately 2,000 satellites estimated to be in orbit currently. Stoltenberg has stressed that NATO has no intention of deploying weapons in space and that NATO's approach will remain defensive and in line with international law. Others have questioned whether China, which has a growing presence in space, might view the NATO declaration as a provocation. A primary focus of the Trump Administration's policy toward NATO has been to urge allies to increase their national defense budgets in line with past agreements intended to ensure an equitable distribution of defense responsibilities within the alliance. In London, President Trump continued these calls but also welcomed substantial increases in European allies' defense spending over the past five years. Secretary General Stoltenberg has credited President Trump with playing a key role in spurring increases in European allied defense spending over the past five years. However, critics of the U.S. President express concern that his strident criticism of what he considers insufficient defense spending by some allies could damage NATO cohesion and credibility. In 2006, NATO members informally agreed to aim to allocate at least 2% of gross domestic product (GDP) to their national defense budgets annually and to devote at least 20% of national defense expenditure to procurement and related research and development. These targets were formalized at NATO's 2014 Wales Summit, when the allies pledged to halt declines in defense expenditures and "move towards the 2% guideline within a decade." U.S. and NATO officials say they are encouraged that defense spending by European allies and Canada has grown for five consecutive years (see Figure 1 ). According to Secretary General Stoltenberg, European allies and Canada have added $130 billion in defense spending since 2014; the figure is expected to rise to $400 billion by the end of 2024. In 2014, three allies met the 2% guideline; in 2019, 9 allies are expected to have met the 2% guideline, and 16 allies are expected to have met the 20% benchmark for spending on major equipment. President Trump and others continue to criticize those NATO members perceived to be reluctant to achieve defense-spending targets, however. One such member is Europe's largest economy, Germany, which currently spends about 1.38% of GDP on defense and has plans to reach 1.5% of GDP by 2024. Although all allied governments agreed to the Wales commitments, many, including Germany, emphasize that allied contributions to ongoing NATO missions and the effectiveness of allied military capabilities should be considered as important as total defense spending levels. For example, an ally spending less than 2% of GDP on defense could have more modern, effective military capabilities than an ally that meets the 2% target but allocates most of that funding to personnel costs and relatively little to ongoing missions and modernization. Analysts on both sides of the Atlantic also have argued that a relatively narrow focus on defense inputs (i.e., the size of defense budgets) should be accompanied by an equal, if not greater, focus on defense outputs (i.e., military capabilities and the effectiveness of contributions to NATO missions and activities). The alliance's target to devote at least 20% of each member's national defense expenditure to new equipment and related research and development reflects this goal. Secretary General Stoltenberg has emphasized a broad approach to measuring contributions to the alliance, using a metric of "cash, capabilities, and contributions." Proponents of this approach argue that a broad assessment of allied contributions that takes into account factors beyond the 2% of GDP defense spending metric would be more appropriate given NATO's wide-ranging strategic objectives, some of which may require capabilities beyond the military sphere. In London, allied leaders approved a U.S. proposal to reduce assessed U.S. contributions, and increase German contributions, to NATO's relatively small pot of common funds . National contributions to NATO's common fundsâabout $2.6 billion total in 2019âpay for the day-to-day operations of NATO headquarters, as well as some collective NATO military assets and infrastructure. According to NATO, in 2018, the U.S. share of NATO's common-funded budgets was about 22% , or about $570 million, followed by Germany (15%), France (11%), and the UK (10%). The U.S. proposal approved in London would bring both the U.S. and German contributions to about 16% each. In London, the allies renewed their commitment to NATO's ongoing training mission in Afghanistan, despite speculation about a possible drawdown of U.S. forces in the country. In January 2015, following the end of its 11-year-long combat mission in Afghanistan, NATO launched the Resolute Support Mission (RSM) to train, advise, and assist Afghan security forces. Between 2015 and late 2018, NATO allies and partners steadily matched U.S. increases in troop levels to RSM. As of February 2020, about 8,500 of the 16,551 troops contributing to RSM were from NATO members and partner countries other than the United States. After the United States (8,000 troops), the top contributors to the mission were Germany (1,300), the UK (1,100), Italy (895), non-NATO-member Georgia (871), and Romania (797). NATO leaders welcomed the February 29, 2020, Joint Declaration between the United States and Afghanistan and agreement between the United States and the Taliban in pursuit of a peaceful settlement to the conflict in Afghanistan. Secretary General Stoltenberg said that NATO would implement adjustments, including troop reductions, to its mission as outlined in the agreements; he stressed, however, that such actions would be "conditions-based." NATO continues to "reaffirm its longstanding commitment to Afghanistan and ongoing support for the Afghan National Defense and Security Forces." In the past, European allies have expressed concern that they were not consulted on possible drawdown plans and stressed that any such plans be carried out in close coordination with the allies. President Trump consistently has called on NATO to expand its counterterrorism efforts beyond Afghanistan, and terrorist threats emanating from the Middle East and North Africa (MENA) region are key European concerns as well. Over the past several years, NATO leaders have launched several new initiatives aimed at countering terrorism and addressing instability in the MENA region. These initiatives include the noncombat NATO Training Mission in Iraq, carried out by between 300 and 500 allied military trainers; the Package on the South, an initiative that includes a range of partnership activities to enhance cooperation initiatives with MENA countries such as Tunisia and Jordan; and establishment of a NATO Regional Hub for the South in Naples, Italy, to coordinate NATO responses to crises emanating from the South. NATO also has deployed aerial surveillance aircraft (AWACS) to assist the global coalition fighting the Islamic State terrorist organization. Several factors have limited enhanced NATO engagement on security challenges emanating from the MENA region. These factors include a belief among some allies that the EU is the appropriate institution to lead Europe's response to terrorism and migration issues and a related reluctance to cede leadership on these issues to NATO. France, for example, has advocated strong European responses to terrorism and conflict in the Middle East but has generally opposed a larger role for NATO. Some allies also disagree on what the appropriate response should be to some of the security challenges in the MENA region, with some appearing hesitant to involve NATO in a way that could be seen as endorsing military action. The Trump Administration and some Members of Congress have urged NATO to assess the security implications of growing Chinese investment in Europe and to work to counter potential negative impacts on transatlantic security. As expressed in the December 2017 U.S. National Security Strategy , U.S. officials have grown increasingly concerned that "China is gaining a strategic foothold in Europe by expanding its unfair trade practices and investing in key industries, sensitive technologies, and infrastructure." U.S. officials express particular concern about Chinese investment in critical infrastructure and telecommunications systems, such as 5G networks. Some U.S. defense officials have suggested that the United States might limit military cooperation and intelligence sharing with allies that allow Chinese investment in 5G networks. In London, NATO formally adopted an October 2019 plan by NATO defense ministers to update the alliance's baseline requirements for civilian telecommunications to reflect emerging concerns about 5G technology. The allies agreed to assess the risks to communications systems associated with cyber threats, and the consequences of foreign ownership, control, or direct investment. Although the EU is attempting to develop common guidelines to govern contracting decisions on 5G networks, these decisions would remain the prerogative of individual national governments. As noted above, U.S. officials have warned European allies and partners that using Huawei or other Chinese 5G equipment could impede intelligence sharing with the United States due to fears of compromised network security. Although some allies, such as the UK and Germany, have said they would not prevent Chinese companies from bidding on 5G contracts, these allies have stressed that they would not contract with any companies that do not meet their national security requirements. On January 28, 2020, the UK government announced that "high-risk vendors" including, but not limited to, Huawei, would be excluded from sensitive "core" parts of 5G networks and locations deemed critical national infrastructure, and that such vendors' access to nonsensitive parts of networks would be limited to 35%. Other countries, such as Poland, have considered formally excluding Huawei from their telecommunications sector, and Czech Republic intelligence officials publicly labeled Huawei a national security risk. Despite U.S. concerns about China's growing footprint in Europe, Administration officials have expressed optimism that the United States and Europe can work together to meet the various security and economic issues posed by a rising China. Analysts, too, cite numerous concerns shared on both sides of the Atlantic and contend that joint U.S.-European pressure on China would be more effective than either partner's individual dealings with China. On March 27, 2020, North Macedonia became NATO's 30 th member (see Figure 2 for a map of NATO members and accession dates). NATO officials had hoped North Macedonia's accession would be complete in time for the London Leaders' Meeting, but elections in some member states delayed the accession ratification process. The U.S. Senate approved U.S. ratification on October 22, 2019. Deliberations in London drew attention to heightened tension and divergent views within the alliance on a range of issues, including U.S. policy toward NATO and Europe, Turkey's standing as a member of the alliance, EU security and defense policy, and NATO's relations with Russia. Disagreement within the alliance on whether and how to respond to these and other issues has prompted some, including French President Emmanuel Macron, to question NATO's strategic direction and future. Many officials and analysts on both sides of the Atlantic also have suggested that President Trump's vocal criticism of NATO and the lack of transatlantic coordination on policies related to Syria and Afghanistan have seriously undermined the alliance. Secretary General Stoltenberg and others maintain that disagreement among allies is not a new phenomenon and stress that "Europe and North American are doing more together in NATO today than we have for decades." In an apparent effort to address diverging views within NATO, in London, the allies agreed to initiate a "forward-looking reflection process â¦ to further strengthen NATO's political dimension including consultation." On March 31, 2020, Secretary General Stoltenberg announced the appointment of a group of 10 experts tasked with recommending ways to "reinforce Alliance unity, increase political consultation and coordination between Allies, and strengthen NATO's political role. The group will be cochaired by former U.S. Assistant Secretary of State Wess Mitchell and former German Interior and Defense Minister Thomas De MaziÃ¨re. Some analysts and allied leaders question the Trump Administration's level of commitment to NATO and express concern that President Trump's criticisms of the alliance could cause lasting damage to NATO cohesion and credibility. In addition to admonishing European allies for failing to meet agreed NATO defense spending targets President Trump has repeatedly questioned NATO's value to the United States. Although he is not the first U.S. President to press the allies to increase defense spending, none has done so as stridently and none has called into question the U.S. commitment to NATO as openly or to the same extent as President Trump. In London, President Trump expressed that his Administration remains committed to NATO and to upholding European security, including through increased funding for U.S. defense activities in Europe such as the European Deterrence Initiative (EDI). Some NATO member state governments argue that growing divergence between the United States and many European allies on a range of key foreign and security policy issues, from Iran's nuclear program to fighting the Islamic State terrorist organization in Syria, has impeded cooperation in NATO and exposed strategic rifts within the alliance. Some European allies have expressed particular concern about what they portray as a lack of U.S. coordination on policy in Syria, where many European countries have been fighting alongside the United States to counter the Islamic State. Some maintain that the U.S. drawdown of forces in Syria in October 2019 enabled Turkey's subsequent military operations against Kurdish forces in the country. In a widely reported November 2019 interview, French President Macron cited these divergences when he proclaimed that, "we are currently experiencing the brain death of NATO." Referring to concerns about the drawdown of U.S. forces from Syria in October 2019 and subsequent military operations by Turkey, he lamented, "You have partners together in the same part of the world, and you have no coordination whatsoever of strategic decision-making between the United States and its NATO allies. None. You have an uncoordinated aggressive action by another NATO ally, Turkey, in an area where our interests are at stake. There has been no NATO planning, nor any coordination." In London, President Trump characterized Macron's criticism as "very, very nasty" and stressed that "NATO serves a great purpose"; Macron said he stood by his earlier criticism of the alliance. Some of Turkey's fellow NATO members have sharply criticized Turkey's October 2019 military operations against Kurdish forces in northern Syria as well as its planned deployment of a Russian S-400 air defense system, with some policymakers calling into question Turkey's qualification for continued membership in the alliance. Turkey has been a NATO member since 1952 and has participated in numerous NATO missions, including ongoing operations in Afghanistan, Iraq, and the Western Balkans. NATO, in turn, has invested substantially in military facilities in Turkey, including naval bases and radar sites. Since 2013, NATO members have provided Turkey with air defense support through the deployment of defensive missile systems along its southern border. During an October 11, 2019, visit to Turkey, Secretary General Stoltenberg acknowledged Turkey's "legitimate" security concerns but urged Turkey to "act with restraint" and do everything it can to preserve the gains that have been made against the Islamic State. Since 2012, Turkey has on three separate occasions invoked Article 4 of NATO's founding treaty to prompt high-level NATO consultations on a perceived threat from Syria to Turkey's territorial integrity or security. On February 28, 2020, the allies met and expressed full solidarity with Turkey in response to "indiscriminate air strikes by the Syrian regime and Russia in Idlib province." Secretary General Stoltenberg stressed that NATO allies were providing Turkey with air defense support along its border with Syria and aerial surveillance over Syria. NATO has deployed up to three air defense systems along the Turkish-Syrian border since early 2013 in response to a Turkish request for support following shelling by Syrian forces and the shooting down of a Turkish fighter jet in 2012. Although the air defense mission continues, some allies cast doubts on the deployment after Turkey's military incursion into northern Syria in October 2019. Italy withdrew its air defense system from Turkey in December 2019, though it said the decision was not a response to Turkey's actions; Spain continues to deploy a Patriot missile battery along Turkey's border. Secretary General Stoltenberg has said that Turkey's acquisition of the S-400 air defense system is "not good" for NATO, but he stressed that Turkey could continue to participate in NATO's integrated air and missile defense systems if the S-400 is excluded from these systems. Some allied leaders have argued that NATO should exclude Turkey from NATO's defense systems if it deploys the S-400. The North Atlantic Treaty does not contain provisions explicitly authorizing NATO allies to take action against another NATO member without its consent. However, the United States and other NATO members could take measures to affect the character of allied cooperation with Turkeyâfor example, by changing their contributions of equipment or personnel, or their participation in specific activities in Turkey. On October 14, 2019, U.S. Defense Secretary Mark Esper stated that he would "press our other NATO allies to take collective and individual diplomatic and economic measures in response to these egregious Turkish actions." Some European leaders, including French President Macron, have argued that uncertainty about the future U.S. role in European security should add urgency to long-standing efforts to develop coordinated European defense capabilities and policies, independent of but complementary to NATO. For two decades, the EU has sought to develop its Common Security and Defense Policy to bolster its common foreign policy, strengthen the EU's ability to respond to security crises, and enhance European military capabilities. Improving European military capabilities has been difficult, however, especially given many years of flat or declining European defense budgets. In recent years, the EU has announced several new defense initiatives, including a European Defense Fund (EDF) to support joint defense research and development activities and a new EU defense pact (known as Permanent Structured Cooperation, or PESCO) aimed at spending defense funds more efficiently. Secretary General Stoltenberg has expressed support for further EU defense integration and cooperation but emphasizes that these efforts should strengthen the European pillar within NATOâ22 NATO members are also members of the EUârather than replace or supplant NATO. Stoltenberg also has stressed that EU defense initiatives should be careful not to duplicate NATO capacities and should complement NATO initiatives. In addition, the Trump Administration has expressed concern that the EDF and PESCO could restrict U.S. defense companies from participating in the development of pan-European military projects. Supporters of EU defense integration highlight that PESCO's initial priority projects were identified in consultation with NATO and that several of these projects focus on enhancing military mobility across Europe, a key NATO priority. Congress was instrumental in creating NATO in 1949 and has played a critical role in shaping U.S. policy toward the alliance ever since. Although many Members of Congress have criticized specific developments within NATOâregarding burden-sharing, for exampleâCongress as a whole has consistently demonstrated strong support for active U.S. leadership of and support for NATO. Congressional support for NATO traditionally has buttressed broader U.S. policy toward the alliance. During the Trump Administration, however, demonstrations of congressional support for NATO have at times been viewed primarily as an effort to reassure allies about the U.S. commitment to NATO after President Trump's criticisms of the alliance. For example, during the Trump Administration, both chambers of Congress have passed legislation expressly reaffirming U.S. support for NATO at times when some allies have questioned the President's commitment. Some analysts portrayed House Speaker Nancy Pelosi and Senate Majority Leader Mitch McConnell's joint invitation to Secretary General Stoltenberg to address a joint session of Congress on April 3, 2019, in commemoration of NATO's 70 th anniversary as an additional demonstration of NATO's importance to Congress. Although Congress has expressed consistent support for NATO and its cornerstone Article 5 mutual defense commitment, congressional hearings on NATO in the 115 th and 116 th Congresses have reflected disagreement regarding President Trump's impact on the alliance. Some in Congress argue that President Trump's criticism of allied defense spending levels has spurred recent defense spending increases by NATO members that were not forthcoming under prior Administrations, despite long-standing U.S. concern. Other Members of Congress counter that President Trump's admonition of U.S. allies and his questioning of NATO's utility have damaged essential relationships and undermined NATO's credibility and cohesion. They contend that doubts about the U.S. commitment to the alliance could embolden adversaries, including Russia, and ultimately weaken other allies' commitment to NATO. Critics also have lamented the Administration's reported lack of coordination with its allies on policies that have significant security ramifications for Europe, such as countering the Islamic State in Syria. Despite disagreement over President Trump's impact on the alliance, most Members of Congress continue to express support for robust U.S. leadership of NATO, in particular to address potential threats posed by Russia. Many Members have called for enhanced NATO and U.S. military responses to Russian aggression in Ukraine, and others have advocated stronger European contributions to collective defense measures in Europe. Increasingly, some Members of Congress have questioned whether NATO should take formal action against an ally, such as Turkey, which pursues foreign and defense policies that they believe could threaten alliance security. In light of these considerations, Members of Congress could focus on several key questions regarding NATO's future, including the following: addressing the strategic value of NATO to the United States and the United States' leadership role within NATO; examining whether the alliance should adopt a new strategic concept that better reflects views of the security threat posed by Russia and new and emerging threats in the cyber and hybrid warfare domains (NATO's current strategic concept was adopted in 2010); examining NATO's capacity and willingness to address other security threats to the Euro-Atlantic region, including from the MENA region, posed by challenges such as terrorism and migration; examining the possible consequences of member states' failure to meet agreed defense spending targets; assessing U.S. force posture in Europe and the willingness of European allies to contribute to NATO deterrence efforts and U.S. defense initiatives in Europe, such as the ballistic missile defense program and EDI; examining options to sanction allies that act in ways that jeopardize allied security; revisiting the allies' commitment to NATO's stated "open door" policy on enlargement, especially with respect to the membership aspirations of Georgia and Ukraine; and developing a NATO strategy toward China, particularly given U.S. and other allies' concerns about the security ramifications of increased Chinese investment in Europe.

Summary: Heads of state and government from NATO's 30 member states met in London, United Kingdom (UK), on December 3-4, 2019. Two key goals for the meeting were to commemorate the alliance's past achievementsâ2019 marks NATO's 70 th anniversaryâand to advance efforts to address new and emerging security challenges, including Russian aggression, terrorism and instability in the Middle East and North Africa, and cyber and hybrid threats. The meeting also exposed heightened political tension within the alliance and divergent views on a range of issues, including U.S. policy toward NATO and Europe, relations with NATO member Turkey, and relations with Russia. In the six years since Russia occupied Crimea and invaded Eastern Ukraine, the United States has played a key role in renewing NATO's focus on territorial defense and deterring Russian aggression. Among other measures, NATO member states have deployed an Enhanced Forward Presence (EFP), totaling about 4,500 troops to the three Baltic States and Poland and including increased military exercises and training activities in Central and Eastern Europe. At the behest of the United States, the alliance also has sought to bolster its response to security threats posed by growing instability in the Middle East and North Africa, primarily through partnerships and training activities. NATO continues to lead a "train and assist" mission of about 16,500 troops in Afghanistan. In February 2020, NATO defense ministers agreed to expand NATO's training mission in Iraq, which currently consists of between 300 and 500 military trainers. The London meeting came at a tense time for NATO. Some allied governments argue that growing divergence between the United States and many European allies on a range of key foreign and security policy issues, from Iran's nuclear program to fighting the Islamic State terrorist organization in Syria, has impeded cooperation in NATO and exposed strategic rifts within the alliance. Some European allies have expressed particular concern about what they portray as a lack of U.S. coordination on policy in Syria, where many European countries have been assisting U.S.-led efforts to counter the Islamic State. Many allies also have criticized fellow NATO member Turkey for its military operations in Syria and its acquisition of a Russian-made air defense system. Although many Members of Congress have criticized specific developments within NATOâregarding burden sharing, for exampleâCongress as a whole has demonstrated consistent support for NATO. During the Trump Administration, congressional support at times has been viewed by some as an effort to reassure allies troubled by President Trump's criticisms of the alliance. Over the past several years, both chambers of Congress have passed legislation reaffirming U.S. support for NATO (e.g., H.Res. 397, H.R. 676 , H.R. 5515 / P.L. 115-232 , and H.Res. 256 in the 115 th Congress; S. 1790 / P.L. 116-92 in the 116 th Congress) and in some cases have sought to limit the President's ability to withdraw from NATO unilaterally ( H.R. 676 ; S. 1790 / P.L. 116-92 ). At the same time, Congress continues to assess NATO's utility and value to the United States, and some Members are concerned about key challenges facing NATO, including burden sharing, managing relations with Russia and China, and divergent threat perceptions within the alliance.