At the first Democratic Party convention of 1860, fifty Southern delegates O refused to vote and left the convention.
o voted to secede from the Union.
O nominated their own candidate.
O decided to become Republicans.

true

explanation:

on april 6, 1917, the u.s. joined its allies--britain, france, and russia--to fight in world war i. under the command of major general john j. pershing, more than 2 million u.s. soldiers fought on battlefields in france.