When did the United States declare war on Japan?

The United States declared war on Japan on December 8, 1941.

In the early morning of December 7, 1941, the Japanese navy launched a surprise attack on the U.S. Pearl Harbor Naval Base. At that time, Japan went to war without declaring it, causing heavy losses to the United States. On December 8, 1941, the U.S. Congress passed a resolution formally declaring war on Japan.

After the United States declared war on Japan, China, which had been at war with Japan for many years, also declared war. Nazi Germany and the Kingdom of Italy also declared war on the United States. The two major wars in Europe and Asia coincided. Until 1945, Japan announced its unconditional surrender.

After the United States and China formally declared war on Japan

After Germany, Italy, and Japan signed a military alliance treaty on September 27, 1940, the United States' Far East policy underwent major changes. In October, the United States provided China with a $25 million tungsten sand loan. In November, US President Roosevelt reiterated that he would not recognize the Wang Puppet regime and officially announced that he would lend China US$100 million.

In March 1941, the U.S. Congress passed the Lend-Lease Act, which authorized the president to provide military assistance to countries that opposed fascist aggression. Subsequently, Roosevelt stated that he would provide unconditional assistance to Britain, Greece, China and other countries. In April, Roosevelt signed an order authorizing American soldiers to resign and join the American Volunteer Air Force to China (Flying Tigers) established by Chennault to help China fight the Japanese Air Force.

In April and May, Roosevelt twice approved the provision of military equipment, weapons and ammunition worth more than 90 million US dollars to China. In July, Roosevelt also approved the provision of equipment and personnel to the Chinese Air Force. In October, the United States sent a military delegation to China, and the U.S. military began to intervene in China's war of resistance.

While the United States stepped up its assistance to China, the U.S.-Japanese negotiations that began in April 1941 completely broke down on November 26. In this way, the United States and Japan finally came to the brink of war. The Pacific War broke out in December 1941, and the United States and China officially declared war on Japan.

Reference for the above content? China News Service-War History Today, December 8: Japanese troops attack Hong Kong and the United States declares war on Japan