Let me share with you a quote I found in Winklopedia-

He overcame the low expectations of many political observers who compared him unfavorably with his highly regarded predecessor. At one point in his second term, near the end of the ... War, ...(his) public opinion ratings reached the lowest of any United States president. Despite negative public opinion during his term in office, popular and scholarly assessments of his presidency became more positive after his retirement from politics and the publication of his memoirs.

Oh, I forgot to mention that this was about President Truman. Hmmm.