"Japan is a significant partner for the United States in a number of foreign policy areas, particularly in terms of security priorities, from hedging against Chinese military modernization to countering threats from North Korea. The post-World War II alliance has long been an anchor of the U.S. security role in Asia. The alliance facilitates the forward deployment of about 49,000 U.S. troops and other U.S. military assets based in Japan in the Asia-Pacific. Until the recent parliamentary elections, Japan struggled to find political stability. Since 2007, six men have been prime minister, including the current premier Shinzo Abe, who also held the post in 2006-2007. His Liberal Democratic Party (LDP) returned to power in a landslide election in December 2012, and cemented their power in parliamentary elections in July 2013. Japan's leaders face daunting tasks: an increasingly assertive China, a weak economy, and rebuilding from the devastating March 2011 earthquake, tsunami, and nuclear disaster. In recent years, opposition control of one chamber of parliament has paralyzed policymaking in Tokyo and made U.S.-Japan relations difficult to manage despite overall shared national interests. Abe is now more free to pursue controversial initiatives that the United States has encouraged such as joining the Trans-Pacific Partnership (TPP) trade pact and increasing its military's capabilities and flexibility."
CRS Report for Congress, RL33436
U.S. Department of State, Foreign Press Center: http://www.fpc.state.gov/