In an Executive Order (E.O. 13767) released during President Donald Trump's first week in office, on January 25, 2017, he declared, "It is the policy of the executive branch to â¦ secure the southern border of the United States through the immediate construction of a physical wall on the southern border â¦ [and] 'Wall' shall mean a contiguous, physical or other similarly secure, contiguous, and impassable physical barrier." The Trump Administration has consistently pursued the deployment of fencing, walls, and other barriers along the U.S.-Mexico border as a high priority. On April 4, 2018, the President, citing "a drastic surge of activity on the southern border," directed the Secretary of Defense, the Attorney General, and the Secretary of Homeland Security to coordinate action on securing the U.S. southern border "to stop the flow of deadly drugs and other contraband, gang members and other criminals, and illegal aliens into this country." The President further directed DOD to mobilize the National Guard to support DHS at the border and to develop a plan for tapping additional military resources using executive authorities. Later that year, as part of budget negotiations over a FY2019 appropriations package, the Administration submitted a supplemental request of $5.7 billion for "construction of a steel barrier for the Southwest border." The new funding request became the focal point of a partial government shutdown that began on December 22, 2018, and lasted 35 days, the longest on record. Unsatisfied with the negotiated agreementâwhich provided $1.375 billion of the Administration's supplemental $5.7 billion requestâPresident Trump declared a national state of emergency and undertook a series of executive actions that redirected $6.1 billion in DOD funds for border barrier construction using a combination of authorities. The Administration's plans were described in a fact sheet entitled, President Donald J. Trump 's Border Security Victory (hereinafter referred to as the factsheet ), and included $2.5 billion in defense funds authorized under (nonemergency authority of) 10 U.S.C. Â§284â Support for counterdrug activities and activities to counter transnational organized crime . $3.6 billion in defense funds authorized under (emergency authority of) Title 10 U.S.C. Â§2808â Construction authority in the event of a declaration of war or national emergency . This report is intended to provide a chronological summary of internal and interagency communication related to DOD's execution of President Trump's border wall funding plan. The information provided here has been drawn chiefly from court exhibits and declarations in ongoing legal proceedings. CRS has not independently authenticated the sworn declarations and accompanying documents submitted by litigants as part of legal proceedings. A declaration in court records describing communications with DOD suggests that DOD anticipated the use of 10 U.S.C. Â§284 to fund border barrier projects in early 2018 when the Under Secretary of Defense (Comptroller) temporarily froze $947 million in unobligated funds from the defense Drug Interdiction and Counter-Drug Activities account for possible construction of barriers on the Southwest Border. The frozen FY2018 appropriations were released beginning in July 2018, the final quarter of FY2018. In April 2018, DOD created a new office within the Department called the b order s ecurity s upport c ell with responsibility for coordinating and managing all border related issues. Assistant Secretary of Defense for Homeland Defense and Global Security, (ASD[HD&GS]) Kenneth Rapuano led the effort. In a letter to DOD dated February 25, 2019, following the release of the Administration's factsheet plan, DHS formally requested that the Defense Department support its ability to impede and deny illegal entry and drug smuggling activities along the southwest U.S.-Mexico border by assisting with the construction (or replacement) of fences, roads, and lighting. DHS specifically requested that DOD fund a total of 11 border barrier projects on federal lands. In a written reply dated March 25, 2019, to Acting Secretary of Homeland Security Kirstjen Nielsen, Acting Secretary of Defense Patrick Shanahan affirmed that the U.S. Army Corps of Engineers (USACE) would undertake the planning and construction of approved projects and, upon completion, hand over custody of all new infrastructure to DHS. Between March and April 2019, DOD approved $2.5 billion for seven of the border barrier projects requested by DHS and funded them in two tranches drawn from reprogrammed defense program savings. DOD completed a transfer of $1 billion for three projects (El Paso Sector Project 1 and Yuma Sector Projects 1-2) on March 26, 2019. On May 9, 2019, the Department completed a second transfer of $1.5 billion for four additional projects (El Centro Sector Project 1 and Tucson Sector Projects 1-3). The obligation of these funds was temporarily suspended by court injunctions between May and July 2019 issued in a lawsuit that challenged the legal basis of DOD's reprogramming actions. On July 26, 2019, the U.S. Supreme Court lifted the lower court's injunction, allowing work to once again proceed. Litigation in this case (and related) lawsuits remains ongoing. In August 2019, DHS notified DOD that new estimates indicated construction costs would be lower than first projected, resulting in an overall funding surplus. DHS requested the anticipated savings be applied to the execution of three additional projects. DOD approved the request but later terminated the plan after savings proved insufficient. On September 30, 2019, DOD announced the transfer of an additional $129 million in expiring FY2019 appropriations drawn from counternarcotics accounts that Military Departments determined were excess to need. The Department also stated USACE would require an additional $90 million in FY2020 funds for the management and oversight of border barrier projects underway. Unlike the Administration's use of the previous $2.5 billion in transfers, which derived largely from defense program savings drawn from non -drug related appropriations, the Administration plans to fund the anticipated costs in FY2020 from appropriations made directly to the counternarcotic account. On January 14, 2020, DHS requested DOD provide additional assistance, pursuant to 10 U.S.C. Â§284, with the construction of 38 new border barrier projects (and project segments) along drug smuggling corridors. On February 13, 2020, DOD approved 31 of these items and reprogrammed $3.8 billion in FY2020 military procurement funds for their execution. All $3.8 billion in reprogrammed funds were drawn from congressional special interest items included in the final FY2020 defense appropriation, P.L. 116-93 . Unlike DOD's use of 10 U.S.C. Â§284 transfer authority, which the Department began executing almost immediately following the release of the President's factsheet , its determination to exercise emergency statute 10 U.S.C. Â§2808 was the result of approximately eight months of additional deliberations. These deliberations included two assessments by the Chairman of the Joint Chiefs of Staff (CJCS) to determine whether the construction of border barriers qualified as a legitimate use under the requirements of 10 U.S.C. Â§2808. The statute specifies that new construction must support the use of armed forces mobilized to address a national emergency declared by the President. On February 11, 2019, CJCS provided a preliminary assessment to the Acting Secretary of Defense that broadly assessed the utility of physical barriers on DHS operations, as well as ongoing demand for DOD support. The report acknowledged empirical challenges associated with quantifying the effectiveness of physical barriers on migration flows "because reliable data is scarce and opinions are divergent," but pointed to anecdotal and historical evidence to suggest that barriers might reasonably be expected to reduce the demand for DOD resources over time: Although military construction projects along the southern border may not alleviate all DHS requirements for DoD support, the construction of physical barriers should reduce the challenges to CBP and, therefore, can be reasonably expected to reduce DHS requirements for DoD support. On February 18, 2019, following the release of the Administration's factsheet plan, DOD requested that DHS provide a prioritized list of projects along with a supplemental analysis explaining how the construction would support military personnel pursuant to 10 U.S.C. Â§2808. DHS responded in March with the detailed information, characterizing the projects as force multipliers for mobilized DOD personnel: Because the requested projects will serve as force multiplier, it will also likely reduce DHS's reliance on DoD for force protection, surveillance support, engineering support, air support, logistical support, and strategic communications assistance. In other words, providing border barriers and the accompanies [sic] roads and technology will allow DoD to focus its efforts on a smaller, more focused area. In April 2019, having received the list of DHS projects, the Secretary of Defense requested the CJCS conduct a second, more detailed analysis of proposed construction and return with a recommendation on how to proceed. Concurrently, the Secretary directed the Under Secretary of Defense (Comptroller) to begin identifying $3.6 billion in existing military construction projects that might be deferred by use of the emergency authority under the statute. In a memorandum report dated May 2019, CJCS General Joseph Dunford delivered his final assessment to Acting Secretary of Defense Shanahan. The report's methodology was based on the presumption that while any barrier construction along the border could reasonably be expected to create "ripple effects" that would support the use of the armed forces, projects more beneficial than others should be prioritized, based on factors identified by DOD. The analysis assessed border barrier projects DHS had requested under 10 U.S.C. Â§2808, as well as those projects not funded by previous transfers under 10 U.S.C. Â§284. Though the CJCS team considered the type of land associated with each project area (federal or private), it developed a prioritization scheme that was missing key details related to land jurisdiction. As a consequence, the CJCS' final recommendations were later revised and included in an action memorandum to the Secretary of Defense on August 21, 2019. On September 3, 2019, Secretary of Defense Mark Esper, having determined that border barrier construction would serve as a "force multiplier" for reducing DHS's demand for DOD personnel and assets, directed the Acting Secretary of the Army to proceed with the construction of 11 DHS border barrier projects, and the deferral of approximately 127 existing military construction projects ($3.6 billion). In a public briefing later that day, DOD officials described a plan for deferring in stages, otherwise authorized military construction projects under 10 U.S.C. Â§2808 authority. Those military construction projects located at non-U.S. locations ($1.8 billion) would be deferred first, followed later by projects within the United States. ($1.8 billion). Officials stated The intent is prioritizing funds in this manner is to provide time to work with Congress to determine opportunities to restore funds, as well as work with our allies and partners on improving burden sharing for overseas construction projects. USACE has noted that the pace for obligating military construction (MILCON) funds for border barrier construction projects will be highly dependent on project location, since land must first be administratively transferred to the Department of the Army before work can proceed. Construction on land that currently falls under the jurisdiction of DOD can be undertaken relatively quickly, since the military effectively manages the parcels. Projects in locations that fall under one or more other federal jurisdictions may be delayed while transfers are negotiated. Projects on private land are expected to take the longest to complete, since the government must first obtain administrative jurisdiction of the land by either purchase or condemnation. On September 18, 2019, Department of the Interior (DOI) issued Public Land Orders that transferred jurisdiction of land required for five of projects for a period of three years to DOD. This section provides a detailed overview of key documents related to the Administration's use of 10 U.S.C. 284 and 10 U.S.C. 2808 to fund border barriers. The tables that follow each include a summary of source documents, citations, and links that allow readers to access the associated materials directly. (Due to technical considerations, documents are only made available to congressional users.) Table 1 , CRS Document Compilations , contains a collection of reference documents that CRS has compiled for the convenience of users. These include court declarations that do not fit neatly into a chronological framework and documents that describe activities that may be grouped as a single action (e.g., multiple reprogramming actions on the same date for an identical purpose). Where Table 1 documents are cited elsewhere in this report, they are identified by the record's "Short Title" shown in the indicated column. Table 2 , Chronology of 10 U.S.C. 284 Decisionm aking , and Table 3 , Chronology of 10 U.S.C. 2808 Decisionmaking, summarize actions related to each respective authority. The separate tables reflect the fact that interagency decisionmaking has generally operated along separate tracks; deliberations related to 10 U.S.C. 2808 were kept separate from correspondence related to 10 U.S.C. 284. 

Summary: The Department of Defense (DOD, or the Department) has contributed $6.1 billion to the construction of new and replacement barriers along the U.S.-Mexico border in support of the Department of Homeland Security (DHS) by invoking a mixture of statutory and nonstatutory authorities. Congressional concerns surrounding the use of these authorities and the further possibility that DOD's actions may jeopardize legislative control of appropriations has generated interest about the decisionmaking process that drove the Department's funding decisions. DOD has not generally made internal and interagency communications related to these processes directly available to congressional staff. However, various letters, memoranda, and explanatory declarations from key decisionmakers have been released into the public record (primarily as the result of ongoing litigation) that provide a more complete picture of the issues the Department considered, along with its final determinations on border barrier funding. This report provides a chronological summary of internal and interagency communications related to DOD's border wall funding processes since approximately April 2018 as described chiefly through court exhibits and declarations in legal proceedings. Due to the technical difficulty of accessing legal records, CRS has made all relevant open source materials accessible to congressional staff via hyperlinks. A comprehensive set of legal citations has also been provided in the accompanying tables.