Europe. For the most part, Europe is a stable, mature, and friendly environment, home to America’s oldest and closest allies. The U.S. is tied to it by treaty, robust economic bonds, and deeply rooted cultural linkages. America’s partners in the region are politically stable; possess mature (if debt-laden) economies; and have fairly modern (though shrinking) militaries. America’s longtime presence in the region, Europe’s well-established basing and support infrastructure, and the framework for coordinated action provided by NATO make the region quite favorable for military operations. The Middle East. In contrast, the Middle East is a deeply troubled area riven with conflict, ruled by authoritarian regimes, and populated by an increasing number of terrorist and other destabilizing entities. Though the United States does enjoy a few strong partnerships in the region, its interests are beset by security and political challenges, surging transnational terrorism, and the potential threat of a nuclear Iran. Offsetting these challenges to some extent are the U.S. military’s experience in the region and the basing infrastructure that it has developed and leveraged for nearly 25 years. Asia. Asia’s defining characteristic is its expanse, covering 30 percent of the globe’s land area. Though the region includes long-standing allies of the U.S. that are stable and possess advanced economies, the tyranny of distance makes U.S. military operations in the region difficult in terms of the time and sealift and airlift that are required. As a whole, the global operating environment currently rates a score of “favorable,” meaning that the United States should be able to project military power anywhere in the world as necessary to defend its interests without substantial opposition or high levels of risk.Russia and China continue to be most worrisome, both because of the investments they are making in the rapid modernization and expansion of their offensive military capabilities and because of the more enduring effect they are having within their respective regions through such actions as Russia’s active involvement in the conflict in Ukraine and China’s provocative building of islands in highly disputed international waters in the South China Sea. North Korea warrants sustained attention not because it has any substantial ability to deploy conventional combat power against the United States directly but because it possesses nuclear weapons capable of reaching U.S. facilities and America’s critical security and economic partners in the region. Furthermore, a conventional war between North Korea and South Korea would have profound consequences for the global economy. Similarly, Afghanistan/Pakistan-based terrorism holds strong potential to spark a large-scale conflict between Pakistan and India (two nuclear powers) or even to pose a nuclear threat to others should radicalized Islamists gain control of Pakistan’s nuclear arsenal or destabilize Pakistan’s government, resulting in the loss of positive control of Pakistan’s inventory of nuclear weapons. Finally, Iran and the various terrorist groups operating in the Middle East would be a greater threat to U.S. security interests than they currently are if they possessed a greater physical ability to project military power outside of their immediate areas. Such a concern is at the heart of the debate over an international agreement pertaining to Iran’s nuclear aspirations. Taken together, the globalized threat to U.S. vital national interests as a whole during 2015 is assessed as “elevated.”Army as “Weak.” The Army’s score dropped from “marginal” last year to “weak” this year, a development that can be attributed primarily to a drop in capacity, as the Army has fewer BCTs ready for deployment abroad. The Army’s capability and readiness scores remained static over the past year as the service continued to struggle with recouping readiness levels after years of budget cuts. Navy as “Marginal.” The Navy again scored strong in readiness, but at a cost to future capability. Deferred maintenance has kept ships at sea, but this is beginning to affect the Navy’s ability to deploy. With scores of “weak” in capability (due largely to old platforms and troubled modernization programs) and “marginal” in capacity, the Navy is currently just able to meet operational requirements. Moving forward, the fleet will be further strained to meet operational demands, especially as Reagan-era platforms increasingly near the end of their service lives. Air Force as “Marginal.” In 2015, the Air Force flew sorties in support of many named operations, resulting in a higher than anticipated operational tempo. The USAF scored “very strong” in capacity. Capability scored as “marginal,” remaining static since last year’s assessment, while “readiness” dropped from “strong” to “marginal.” Although difficult to categorize, the readiness decline is best attributed to reports that under half of the service’s combat air forces meet full-spectrum readiness requirements. The aggregate score of “marginal” is a decline from the 2015 Index score of “strong”, driven primarily by degradation in capability and readiness. Marine Corps as “Marginal.” As with last year, the Corps’ strongest suit was in readiness, but even here there are problems as stated by the Corps itself. While the fighting competence of the service is superb, it is hampered by aging equipment; troubled replacement programs for its key ground vehicles (particularly its amphibious personnel carriers); and a shrinking force. The progress the Corps has made in replacing its rotary-wing aircraft has been a notable bright spot in its otherwise uninspiring modernization portfolio. Nuclear Capabilities as “Marginal.” Modernization, testing, and investment in the intellectual/talent underpinnings of this sector are the chief problems facing America’s nuclear enterprise. Delivery platforms are good, but the force depends on a very limited set of weapons (in number of designs) and models that are quite old, in stark contrast to the aggressive programs of competitor states. Following developments abroad in regions of national interest and increased uncertainty globally, there is now a greater need to modernize U.S. nuclear capabilities, particularly with regard to aging delivery systems. Continued reliance on legacy systems such as the B-52 will eventually diminish the effectiveness of the nuclear triad and lead to the degradation of our nation’s strategic deterrence.