I disagree. Take Bush for example. He personally fucked up the US by being a bully. Lots of power. Obama could be more forceful.
What kind of weed are you smoking these days? Any power he had was given to him by congress (Iraq War), and most of the completely heinous things of the Bush era (tax cuts, military spending, Patriot Act, TARP, etc.) were all acts of Congress.
I suppose you could argue that he was responsible for several major executive blunders (lax FTC enforcement, extraordinary rendition, poor military execution, etc.) but these could have been reigned in by congress, had they even bothered. Hell, most of these things were only possible because of congress, who basically gave him a blank check.