For nearly five decades following Indian independence in 1947, the United States and India struggled to find common ground for a fruitful relationship. Prevailing geopolitical conditions during the Cold War undermined the potential for sustained bilateral engagement. Dramatic geopolitical changes after the fall of the Soviet Union opened diplomatic space for major new collaborative initiatives between the United States and India. Symbolic of these changes, the two countries have since 2004 been pursuing a "strategic partnership" that incorporates numerous economic, security, and global initiatives. The United States views security cooperation with India in the context of common principles and shared national interests and strategic objectives such as defeating terrorism, preventing weapons proliferation, and maintaining regional stability. After initial uncertainty under President Barack Obama, senior Pentagon officials assured New Delhi that the current administration is fully committed to strengthening ties through the enhancement of the defense relationship made substantive under President George W. Bush. U.S.-India engagement on shared security interests is a topic of interest to the U.S. Congress, where there is considerable support for a deepened U.S. partnership with the world's largest democracy. Congressional advocacy of closer relations with India is generally bipartisan and widespread; House and Senate caucuses on India and Indian-Americans are the largest of their kind. Caucus leaders have encouraged the Obama Administration to work toward improving the compatibility of the U.S. and Indian defense acquisitions systems, as well as to seek potential opportunities for co-development or co-production of military weapons systems with India. This report includes a brief outline of American security interests in relation to India, followed by an in-depth discussion of India's strategic interests and defense posture. These sections provide context for a review of the variously convergent and divergent strategic interests of both countries. It also discusses non-geopolitical obstacles to more substantive cooperation across the partnership, including mutual mistrust and bureaucratic misunderstanding. It concludes with a brief discussion of the outlook for future security bilateral cooperation. A companion piece to this report—CRS Report R42823, India-U.S. Security Relations: Current Engagement , by [author name scrubbed] and [author name scrubbed]—discusses the details of current U.S.-India security engagement. In the early decades following Indian independence, the potential for positive security relations between Washington and New Delhi was hindered by three largely intertwined disagreements: The first was rooted in the all-consuming Cold War calculus and ostensibly nonaligned India's Soviet tilt (the latter being a function of India's strongly-held anti-colonialist sentiments following nearly a century under London's direct rule as the "crown jewel" of the British Empire). Added to these were Washington's close ties with Pakistan, India's most contentious rival, and the discomfort these elicited in New Delhi. Finally, New Delhi's abstention from the 1970 Non-Proliferation Treaty (NPT) and subsequent pursuit of nuclear weapons capability fueled American fears of further proliferation and the emergence of a destabilizing nuclear arms race on the Asian subcontinent. It was through this nuclear nonproliferation prism that the United States regarded India for decades to follow. The 1989-1991 collapse of the Soviet Union nominally eliminated a major geostrategic obstacle to closer U.S.-India relations. Nonetheless, the end of the Cold War initially set the United States and India on largely incompatible paths. Western democratic and free market ideals no longer faced any major ideological challenger with the demise of the Soviet Bloc. As the world's sole superpower, the United States acted to define and consolidate its Cold War victory. For Washington, this meant promoting liberal political and economic systems abroad with an eye toward winning dividends for U.S. prosperity and security at home. In the early 1990s, India emerged from the losing side of the Cold War. Cash-strapped and on the verge of economic collapse without its Soviet benefactors, New Delhi turned away from its traditionally statist economy and began to gradually incorporate itself into the liberal order, a move that no longer allowed New Delhi to distance itself from Washington. While India had begun normalizing relations with the United States in the 1980s, the precipitous Soviet collapse meant a sudden end to Moscow's financial support for India, compelling New Delhi's leaders to engage the West despite long-running fears of jeopardizing India's strategic autonomy. In the new geopolitical environment, the U.S.-India defense ties that began in the mid-1980s grew slowly. The impetus for sustained relations notably emerged from the U.S. Pacific Command (PACCOM). In 1991, PACCOM's Army commander, General Claude Kicklighter, visited India to initiate the first set of concrete proposals establishing cooperation between the U.S. and Indian militaries. The continuation of these threadbare defense ties was significant given the unevenness of the broader bilateral relationship of the period. Around the same time, confrontation between Washington and New Delhi on the NPT and Comprehensive Nuclear-Test-Ban Treaty (CTBT) escalated. In 1995, the Clinton Administration pushed for the indefinite extension of the existing NPT at the United Nations. For India, this meant seemingly permanent nuclear weapons pariah status. From the American perspective, India's continued noncooperation on nuclear proliferation only served to destabilize the South Asia region. Nonetheless, the 21 st century opened with relatively hopeful prospects for U.S.-India relations. To New Delhi's surprise, the Clinton Administration pressured Pakistan into withdrawing its forces following the 1999 Kargil war in the disputed Kashmir region. Then, in 2000, President Bill Clinton made a landmark visit to India, becoming the first U.S. President to visit the country in 22 years. Immediately prior to the visit, the Administration had eased U.S. sanctions on India related to its 1998 nuclear tests. In his speech to the Indian Parliament, President Clinton referred to India as a "natural ally" and identified numerous shared values and potential areas for cooperation between the two countries. That same year, the U.S.-India Joint Counterterrorism Working Group was established, formalizing an area of cooperation that long existed. While President Clinton's visit was generally considered successful, it did not have a transformational effect. His Administration's policies toward India remained mired in balancing the Indo-Pakistani rivalry and addressing concerns about the region's nuclear arsenals, despite Washington's optimistic intentions and increasing realization of shared interests with India. Prior to the terrorist attacks of September 2001, the wheels of the U.S.-India relationship were thus steadily, albeit gradually, in motion. The incoming Bush Administration further energized Clinton's pro-India policies. When Indian External Affairs Minister Jaswant Singh met with National Security Advisor Condoleezza Rice in April 2001, President George W. Bush met informally with Singh in the Oval Office, a gesture most welcome by New Delhi. The next month, Deputy Secretary of State Richard Armitage made a stop in India to garner approval for the Bush Administration's controversial missile defense plans. Instead of seizing upon an opportunity to publicly criticize Washington for its perceived hypocrisy with regard to relevant international agreements, Singh welcomed the policy and contended that the two countries were "endeavoring to work out together a totally new security regime which is for the entire globe," a notion heretofore unimaginable in the context of the U.S.-India relationship. While many U.S. allies criticized America's missile defense policy, India conspicuously, if only rhetorically, stood by Washington's side. Nevertheless, the catastrophic events of 9/11 posed a major test of the budding friendship. On one hand, the attacks brought into clear relief a growing realization of common strategic interests and vulnerabilities related to Islamist terrorism. On the other hand, Pakistan reemerged as a key geopolitical facilitator of U.S.-led military efforts in Afghanistan. Thus, a key question in New Delhi was, "With whom will the Americans align themselves?" Just days after 9/11, Washington waived proliferation-related sanctions for both India and Pakistan (the latter country also benefitted from the waiver of democracy- and debt arrearage-related sanctions). Despite this sudden readjustment in bilateral ties, Indian leaders felt resentment and became concerned that the United States was appeasing Pakistan and ignoring New Delhi's concerns about what they saw as Pakistan-supported terrorism in India. For its part, Washington was consumed with responding to the 9/11 attacks, in part by securing Pakistan's cooperation in Afghanistan. The crux of the challenge for Washington "was to avoid either leaning on Pakistan too hard, which could hurt [operations] in Afghanistan, or not leaning on Pakistan hard enough, which would alienate New Delhi." It was a tall order considering the extent to which the situation had deteriorated after Pakistan-based terrorists attacked India's Parliament complex in December 2001. Yet, by the opening month of 2002, the United States had managed to secure India's restraint while also eliciting a pledge to tackle terrorism from Pakistan's military ruler. Throughout much of the Bush Administration's first term, the balancing act between India and Pakistan continued to be evident in U.S. policy toward South Asia. A major breakthrough in the U.S.-India relationship came soon after President Bush's re-election. In July 2005, President Bush and Prime Minister Manmohan Singh issued a Joint Statement resolving to establish a "global partnership" between the United States and India, through increased cooperation on numerous issues, including "full civilian nuclear energy cooperation" (such cooperation would require changes in both U.S. law and international guidelines). The "Next Steps in Strategic Partnership" (NSSP) initiative involved progress through a series of reciprocal steps in which both countries took action designed to expand engagement on nuclear regulatory and safety issues, enhanced cooperation in missile defense, peaceful uses of space technology, and creation of an appropriate environment for increased high-technology commerce. Sanctions that remained after the 2001 easing were rolled back further.