In 1916 Robert La Follette Sr. tried to get the Republican nomination. At the time, he was a prominent Anti-War voice. The Republican nomination went to Charles Evans Hughes, who was more militaristic. What if after losing the nomination, La Follette ran as a third party candidate on a peace platform? Being a Republican, it seems like La Follette would steal votes from Hughes and guarantee a victory for Wilson like in OTL. However, Wilson largely ran on keeping the US out of the war, so a pro-peace third party might act as a spoiler for him. 1916 was a close election. If 4000 votes shift in California, the election would go to Hughes. The POD doesn't necessarily have to be La Follette running as a third party. Any Pro-Peace candidate will do. I know Henry Ford was a pacifist and had some political ambitions.