Depends on your definition of "worst". Certainly Clinton has to rank right up there. Carter takes the cake for wrong headed decisons. But Clinton sold the country to the Chinese and was just inattentive to duty for 8 years. Looks like a tie to me, except that we suffered under Clinton longer!
Clinton was a very bad person, Carter was a very bad president.
Clinton left the economy alone and let it grow. I was always better off 4 years after anytime of the Clinton presidency. Carter almost ruined me and just about anyone I knew.
Carter was depressing for the soul as well as the economy.
We were never so close to becoming part of the Soviet Union as we were with Carter.