Created Wilsonian doctrine that led to forever wars
Segregated the federal government.
Wrote Southern Revisionism
Fostered the second founding of the KKK
Erected a bunch of statues of traitors that specifically said to never erect statues of them.
Probably caused Lenin, and Stalin thereby causing Hitler and WWII plus a host of downstream knock-on effects such as The Cold War and the demonization of socialism and communism in the US.
Robbed us of Teddy’s third and fourth terms in office.