The title and contents really speak for themselves, but I'll quote Frank Rich (from The New York Times) anyway:
Bush kept America safe (provided his presidency began Sept. 12, 2001). He gave America record economic growth (provided his presidency ended December 2007). He vanquished all the leading Qaeda terrorists (if you don’t count the leaders bin Laden and al-Zawahri). He gave Afghanistan a thriving “market economy” (if you count its skyrocketing opium trade) and a “democratically elected president” (presiding over one of the world’s most corrupt governments). He supported elections in Pakistan (after propping up Pervez Musharraf past the point of no return). He “led the world in providing food aid and natural disaster relief” (if you leave out Brownie and Katrina).