Diplomatic relations between the United States and Japan began to deteriorate in the early 20th century due to competing economic and military interests in the Pacific region.
The tensions came to a head in 1941 when Japan launched a surprise attack on the US naval base at Pearl Harbor, Hawaii, leading to the United States entering World War II. During the war, the US and Japan were bitter enemies, with intense fighting in the Pacific theater.
After the war ended in 1945 with the dropping of atomic bombs on Hiroshima and Nagasaki, Japan surrendered unconditionally to the Allies, including the United States. The US occupied Japan and oversaw its reconstruction and democratization.
Over time, diplomatic relations between the two countries improved, as Japan became a key ally of the United States in the Cold War and beyond. The two countries signed a security treaty in 1951, which allowed for the presence of US military bases in Japan.
Today, the United States and Japan have a strong and enduring alliance, based on shared democratic values and mutual security interests. The two countries cooperate closely on a range of issues, including defense, trade, and diplomacy, and maintain a robust economic partnership. While there have been some tensions and disagreements over the years, the overall relationship between the US and Japan remains a cornerstone of stability in the Asia-Pacific region.