The worst ever?

Eminent historian Eric Foner suggests that Bush is the worst President in the history of the country:

Historians are loath to predict the future. It is impossible to say with certainty how Bush will be ranked in, say, 2050. But somehow, in his first six years in office he has managed to combine the lapses of leadership, misguided policies and abuse of power of his failed predecessors. I think there is no alternative but to rank him as the worst president in U.S. history.

I don't know if I'd go so far as to rank Bush below Andrew Johnson, but that certainly does seems to be the league he's playing in.