"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. After years of turmoil, Japanese politics appears to have entered a period of stability with the December 2012 election victory of current premier Shinzo Abe and his Liberal Democratic Party (LDP). New elections are not required to be held until 2016. Japan's leaders face daunting tasks: an increasingly assertive China, a weak economy, and rebuilding from a devastating March 2011 earthquake, tsunami, and nuclear disaster. In recent years, opposition control of one chamber of parliament paralyzed policymaking in Tokyo and made U.S.-Japan relations difficult to manage despite overall shared national interests. However, the LDP's recent election victories have given it control over both chambers, thereby giving Abe more political room 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