What group of political leaders opposed the entry of the US into World War 1?

There were several political "leaders" who opposed US entry into World War One. The Progressive Party split, with Teddy Roosevelt leading those who favored entry into the war and western Progressives, LaFollette, Norris, Borah, and Johnson, fighting against a declaration of war. There were a group of politicians and citizens who believed we could ignore the military activities of Europe. They were known as "isolationists." An example was William Jennings Bryan. There were a very organised group of pacifists who opposed the war, led by Montana congresswoman Jeannette Rankin. She and over 50 of her colleagues in Congress voted against entering the war. Not all were pacifists, but many agreed with her that this conflict would resolve nothing, so they all voted against it.