The U.S.-Japan Security Treaty, signed in 1960, is a bilateral agreement between the United States and Japan that establishes mutual defense obligations. Under this treaty, the U.S. is committed to defending Japan in the event of an armed attack, while Japan allows the U.S. to maintain military bases on its territory. This treaty plays a crucial role in maintaining stability in the Asia-Pacific region. It reflects the strategic partnership between the two nations, promoting cooperation in defense and security matters, and has been a cornerstone of Japan's post-World War II security policy.