"William Howard Taft running for US president:

Prior to ww1, the US elections took place with Woodrow Wilson winning with a 36% (give or take) majority, how could this happen? Taft. The election was split 3 ways, Wilson for the democrats, and Taft and Teddy Roosevelt for the Republicans, they split the vote and Wilson Won. Had Taft not split the vote Roosevelt would have won and serve a third presidential term. As president, Roosevelt would have almost definitely pushed the US one WW1 much earlier than Wilson did, possibly shortening the war by up to a year. The main impact of this would have been on Russia, while it wouldn’t have saved the Tsar, it would have put down Lenin and prevented the rise of Communism, as it would have denied Lenin the public backing he needed, given that the current govt. didn’t look quite so incompetent. With no Lenin, no Stalin, no mass genocides, speaking of genocides, the fear of communist take-over largely fuelled support for the Nazi party and without them, Hitler would have lived and died a fringe extremist with very few people even noticing him.

TLDR; Taft ran for president, split the vote, denied Roosevelt a third term, which lead to a prolonged WW1, the Russian Communist take over, WW2, Cold War, etc."