He allowed his chief of staff to take bribes (the vicuña coat)
He expanded Truman's lip service "Loyalty Order" to cover all federal employees and to include far more broad definitions of "disloyal" behavior and authorized the FBI to investigate allegations under it, thus giving Joe McCarthy free reign to ruin people's lives
He put the full weight of the White House behind the fully corrupt Dixon-Yates plan
He picked a VP who was already busy in 1952 trying to convince people he wasn't a crook
He let the Soviets install a puppet government in Cuba, less than 100 miles from the continental US
He stuck the first US fist into the Vietnam tar baby