Let History Judge
But the lowest since they've been measured belongs to "Give 'Em Hell" Harry Truman, who is generally considered by historians to be a pretty decent president.
Truman's unpopularity was certainly tied to the Korean War that, in the long run, saw 58,000 Americans killed.
Preventing South Korea from being overrun by the communists of the North was certainly a good thing for the citizens of that now properous country. Especially compared to the gulag that passes for a country under Kim Jong Il.
History has been kind Truman. Whether it is as kind to George Bush will depend on whether Iraq continues on its path to being the only functioning Arab democracy in the Middle East.
We will see.