CRS – The United Kingdom: Background and Relations with the United States, Derek E. Mix, Analyst in European Affairs. March 27, 2015.

“Many U.S. officials and Members of Congress view the United Kingdom (UK) as the United States’ closest and most reliable ally. This perception stems from a combination of factors, including a sense of shared history, values, and culture, as well as extensive and long-established cooperation on a wide range of foreign policy and security issues. In the minds of many Americans, the UK’s strong role in Iraq and Afghanistan during the past decade reinforced an impression of closeness and solidarity.,, In recent years, some observers have suggested that the U.S.-UK relationship is losing relevance due to changing U.S. foreign policy priorities and shifting global dynamics. U.S. officials have expressed increasing concerns about UK defense cuts and their potential effect on future security cooperation. Despite such anxieties, most analysts believe that the two countries will remain close allies that choose to cooperate in many important areas, such as counterterrorism, economic issues, and the future of NATO, as well as numerous global and regional security challenges.”