This report provides background information and potential issues for Congress regarding the growing strategic competition between China and India—the world's two most populous nations—in South Asia and the Indian Ocean Region (IOR). The issue for Congress is how the United States should respond to this strategic rivalry and what role Congress might play in shaping that response. Sino-Indian strategic competition in the IOR poses several specific policy and oversight issues for Congress. Decisions that Congress makes on these issues could affect numerous aspects of U.S. policy, including U.S. relations with India, China, and other countries in the region; U.S. defense programs and spending levels; U.S. arms sales and foreign assistance programs; and U.S. trade and energy policy. Other CRS reports cover related issues, such as U.S.-China relations, U.S-India relations, U.S. relations with other countries in the IOR, China's military forces, and other specific issues relating to U.S. policy and this part of the world. A central long-term tenet of U.S. strategic thinking has been that the United States cannot allow any one power, or coalition of powers, to dominate the Eurasian land mass, as such a power or coalition would have the ability to significantly threaten the United States and its interests. Geopolitical thinkers have long debated the importance of the Eurasian littoral in influencing the strategic direction of the Eurasian landmass. (For more on geopolitics and geo-economics, see Appendix A .) South Asia and the Indian Ocean littoral are a significant part of this broad strategic geography. As such, it is of strategic importance to the United States to understand the evolving power dynamics related to China-India rivalry in the IOR. The world's geo-economic shift toward Asia, and the related increase in Indian Ocean trade and investment, is increasing the strategic importance of the Indian Ocean Region to many nations. Further, the rapid development of China's economic and military capabilities in the IOR is a source of rivalry and tension. The Indian Ocean is the world's busiest trade corridor, carrying two thirds of global oil shipments and a third of bulk cargo. Approximately 80% of China's, 90% of South Korea's, and 90% of Japan's oil passes through the Indian Ocean. This economic dependence on energy and trade transiting the Indian Ocean has become a strategic vulnerability for these states at a time when the United States is becoming less dependent on imported energy. Under several past administrations, U.S. policy toward the Indo-Pacific has included the following goals and objectives: Shape the strategic dynamics in the IOR as needed to prevent Asia from being dominated by a single hegemon or coalition of powers that could threaten the United States; Support U.S. friends and allies in the region and develop strategic and defense relationships with regional partners to strengthen the U.S strategic standing in the region; Promote a rules-based order and norms that support regional stability; Protect U.S. access to energy supplies; Help maintain freedom of navigation on the high seas and through the strategic choke points of the Indo-Pacific to facilitate the flow of U.S. and global trade and energy resources and the transit of U.S. naval forces; Prevent the region from being used by terrorists as bases of operations; Prevent the proliferation of Weapons of Mass Destruction from the region to state and non-state actors; Prevent large scale conflicts, such as between India and Pakistan, to preserve regional stability and trade; Keep the United States engaged in the dominant economic and strategic architectures of the region to promote U.S. economic interests; Continue to work with like-minded partners to support open societies and promote shared values including the rule of law, human rights, democracy and religious freedom; Conduct counterpiracy operations; and Work with China, India and regional states to address the threat of climate change in bilateral, multilateral, and global contexts. Under the Trump Administration, some of these assumptions and policy positions, such as the importance of climate change, have changed. The United States has significant military assets in the Indian Ocean Region including Camp Lemonnier in Djibouti , which is the primary base of operations for U.S. Africa Command in the Horn of Africa, supports approximately 4,000 U.S. and allied military and civilian personnel. A U.S. Navy Support Facility is located on the British Indian Ocean Territory of Diego Garcia in the Indian Ocean south of India. The facility "provides logistic support to forces forward deployed to the Indian Ocean and Persian Gulf areas of responsibility (AOR)." There are approximately 2,500 U.S. and allied military and civilian personnel on Diego Garcia. Naval Support Activity Bahrain is home to U.S. Naval Forces Central Command (CENTCOM) and the U.S. Fifth Fleet. Naval Support Activity Bahrain provides operational support to U.S. and coalition forces in the CENTCOM AOR. In addition to much of Central Asia and the Middle East, CENTCOM's AOR includes the Persian Gulf, the Red Sea, and the Arabian Sea. The U.S. Pacific Command's (PACOM) AOR extends across much of the Indian Ocean. The United States is also developing a rotational presence of up to 2,500 marines and aircraft near Darwin, on Australia's northern coast, as part of its alliance relationship with Australia. The 2017 National Security Strategy (NSS) of the Trump Administration declares that "great power competition [has] returned" and places significant emphasis on the Indo-Pacific while describing China, along with Russia, as a revisionist power and competitor challenging "American power, influence and interests" while "attempting to erode American security and prosperity." One observer states that, "The biggest departure from previous NSS documents is the placement of the Indo-Pacific discussion—at the very top of the regions considered, above Europe and the Middle East." The NSS states that "China seeks to displace the United States in the Indo-Pacific region, expand the reaches of its state-driven economic model, and reorder the region in its favor." It identifies "a geopolitical competition between free and repressive visions of world order" in the Indo-Pacific. The document also states that "China's infrastructure investments and trade strategies reinforce its geopolitical aspirations." The NSS lists the "Indo-Pacific" as the first of six regional contexts it discusses and states that, "we welcome India's emergence as a leading global power and stronger strategic and defense partner." It goes on to say that the United States will expand and deepen its security cooperation and strategic partnership with India while supporting India's leadership role in the Indian Ocean region. The NSS also states: "We will seek to increase quadrilateral cooperation with Japan, Australia, and India." The NSS takes the view that past assumptions that engagement with rivals through international fora and commerce would turn them into benign partners have, for the most part, turned out to be false. The 2018 National Defense Strategy views the reemergence of long-term, strategic competition by revisionist powers as the central challenge to the United States' prosperity and security. Within this context it states China is leveraging military modernization, influence operations, and predatory economics to coerce neighboring countries to reorder the Indo-Pacific region to their advantage. ... it will continue to pursue a military modernization program that seeks Indo-Pacific regional hegemony in the near term and displacement of the United States to achieve global preeminence in the future. The Defense Strategy prioritizes expanding Indo-Pacific alliances and partnerships to achieve a "networked security architecture capable of deterring aggression, maintaining stability, and ensuring free access to common domains ... and preserve the free and open international system." On October 18, 2017, in a speech described as seeking to establish a foundation for U.S.-India relations over the next century, then-Secretary of State Rex Tillerson stressed the importance of the United States' developing a strategic partnership with India by stating that, "The Trump administration is determined to dramatically deepen ways ... to further this partnership." Tillerson pointed to the annual Malabar naval exercises and growing bilateral defense ties before observing, "The United States and India are increasingly global partners with growing strategic convergence.... The emerging Delhi-Washington strategic partnership stands upon a shared commitment upholding the rule of law, freedom of navigation, universal values, and free trade." In discussing developing ties with India, Tillerson described China's rise as at times undermining the international, rules-based order even as countries like India operate within a framework that protects other nations' sovereignty. China's provocative actions in the South China Sea directly challenge the international law and norms that the United States and India both stand for. The United States seeks constructive relations with China, but we will not shrink from China's challenges to the rules-based order and where China subverts the sovereignty of neighboring countries and disadvantages the U.S. and our friends. In this period of uncertainty and somewhat angst, India needs a reliable partner on the world stage. I want to make clear: with our shared values and vision for global stability, peace, and prosperity, the United States is that partner. Former Secretary Tillerson also raised the issue of "predatory economics" and the related need to counter China's financing mechanisms by providing alternative financing to states. India lauded Tillerson's remarks while China was more critical. Tillerson's affirmation of the strategic partnership between the United States and India builds on bilateral developments of the past several years, over various U.S. administrations.