He certainly has turned out to be a disappointment, but worst president in the nations history? Na thats a split tie between Nixon and Bush Jr with Bush tipping the scales due to having the lowest IQ of any president in the known world.
Comparing Obama to Bush Jr. shows that the former is not much better by any means. I'll also agree that Bush Jr. was the worst president the US ever had. But the economy wasn't much harmed during this reign. But for comparison, 6 years of Obama rule has destroyed the American economy almost beyond any sort of repair.