In his new memoir, Tony Blair says no:
One of the most ludicrous caricatures of George is that he was a dumb idiot who stumbled into the presidency. No one stumbles into that job, and the history of American presidential campaigns is littered with the corpses of those who were supposed to be brilliant but who nonetheless failed because brilliance is not enough. [...]
To succeed in US politics, of that of the UK, you have to be more than clever. You have to be able to connect and you have to be able to articulate that connection in plain language. The plainness of the language then leads people to look past the brainpower involved. Reagan was clever. Thatcher was clever. And sometimes the very plainness touches something else: a simplicity that is the product of a decisive nature.
Despite my unabashed love for jokes that make fun of President Bush's intelligence, I never thought he was a dumb man. Blair is right; genuinely stupid people don't go far in American politics, and no one just stumbles into the presidency of the United States.
Jonathan Bernstein made this point a few months ago, but it's a good one, and worth repeating; decades from now, when the history of the Bush administration has been written, we'll find that George W. Bush suffered from passivity, indifference and incompetence, not stupidity or ignorance. As Bernstein notes, the president's main job is to avoid policy disasters, since policy disasters for the nation are political disasters for the president, and capable presidents are most skilled at avoiding political disasters. Yes, Bush was regularly criticized for his politicized White House, but when it comes down to it, he lacked the political skills it takes to successfully manage the presidency. Bush failed for other reasons too, but a big part of it was that he simply wasn't a very good politician.
-- Jamelle Bouie