Shortly after the bombing of Pearl Harbor, in december of 1941.
Congress
germany
no
Germany
yes
In both.
President Wilson asked congress to declare war on Germany and entered the alied side of the conflict in 1917.
1917
The US Constitution provides that the congress shall declare war. The congress declared war on Germany when Woodrow Wilson was president in 1917 and when Franklin Delano Roosevelt was president in 1941.
Congress wouldn't hear of it.
April 6, 1917
If this question is in reference to World War II, most countries declared war on Germany because Germany declared war on them.