Why did FDR lose support in 1944 from 1940?

[Kevinstat]

He broke a promise and thought he could get away with it. It is the same reason Woodrow Wilson became unpopular in his second term.

Yeah, it's not like the US was attacked by an axis power or something...

That makes a lot of sense. I assume you would characterize going to war after a terrorist organization flies an airplane into an american building in the same context & I understand the differences. With all three those being both American entry into both world wars and the iraq war a symbol of America was attacked. The USS Maine under President Wilson & the Pearl Harbor attack & 9/11.

The explosion of the USS Maine (whether from a Spanish mine or not) happened in 1898 and was a catalyst for the Spanish-American War, not World War I.  I don't think it was the sinking of any single ship that brought the U.S. into WWI, but the fact that Germany made it clear that they would attempt to sink any American ship within the waters of the Allied nations without warning and had followed up on that threat, sinking three merchant ships I believe.  Also the Zimmerman telegram, promising territory in the southwest to Mexico if it joined the war on Germany's side after the U.S. went to war with Germany.