What did germans do that made some americans originally want to get involved in the war?

Is this in reference to world war I or world war II.

If its in reference to world war I, the Americans were neutral until Germany started to use U-boats to sink the ships that Americans would carry supplies on to the other sides.  This angered the Americans and made them enter the war.

In world war II, The germans did not cause the Americans to get involved in the war but instead, the Japanese did with the Bombing of Pearl Harbor

Sub warfare by the germans really angered the Americans. Then, in 1917, the Zimmerman note was discovered, and Woodrow Wilson finally declared war on Germany.