Answer:
They had cultural ties with them; British news/propaganda also swayed the American public opinion in favor of the Allies.
The First Amendement (Freedom of Speech) was the basis for Charles Schenck's 1919 Supreme Court arguments that his distribution of flyers and leaflets during WWI to promote draft resistance among young men was Constitutional.
Schenck was arrested under the Espionage Act of 1917. The Supreme Court upheld the decision finding that draft resistance in the midst of WWI was unconstitutional.
