OK, I found the bit I was remembering: The UK actually declared war on Japan nine hours before the U.S. did, partially due to Japanese attacks on Malaya, Singa

OK, I found the bit I was remembering: The UK actually declared war on Japan nine hours before the U.S. did, partially due to Japanese attacks on Malaya, Singapore, and Hong Kong, and partially due to British Prime Minister Winston Churchill's promise to declare war "within the hour" of a Japanese attack on the United States.[1] I had forgotten the part about the attacks on Malaya, etc. [1]: https://en.wikipedia.org/wiki/Attack_on_Pearl_Harbor#Aftermath https://en.wikipedia.org/wiki/Attack_on_Pearl_Harbor#Afterma...