From the Overview: "Japan, a U.S. treaty ally since 1951, is a significant partner of the United States in several foreign policy areas, particularly security and trade. Shared security goals range from meeting the challenge of an increasingly powerful China to countering threats from North Korea. The U.S.-Japan mutual defense treaty grants the United States the right to base U.S. troops--currently numbering around 50,000--and other military assets on Japanese territory in return for a U.S. pledge to protect Japan's security. The two countries collaborate through multiple bilateral and multilateral institutions on issues such as science and technology, global health, energy, and agriculture. Japan is the fourth largest U.S. trading partner and largest source of foreign direct investment into the United States, and its investors are the largest foreign holders of U.S. Treasury securities. The U.S.-Japan relationship remains strong, and recent leadership transitions in both capitals could smooth relations and deepen cooperation across a greater set of issues. Whereas alliance relations under former President Trump and former Prime Minister Shinzo Abe relied heavily on personal rapport between leaders, President Biden and Prime Minister Yoshihide Suga may revert to a more traditional partnership that relies more on institutionalized ties. [...] In the short term, the countries will confront the expiration of their existing cost-sharing agreement for hosting the U.S. military in Japan."
CRS In Focus, IF10199
Congressional Research Service: https://crsreports.congress.gov/