Jim Pethokoukis of the American Enterprise Institute has updated his chart plotting the Obama administration's predictions of unemployment right now if the American Recovery and Reinvestment Act passed (under 6 percent!), if the stimulus didn't pass (about 6 percent!), and the reality of the situation (8.1 percent!).

The various explanations for why the administration was so far off - the recession was much worse than we expected! the stimulus needed to be bigger all along but we couldn't even suggest that due to GOP opposition! - don't inspire confidence either that President Obama's team ever knew what it was talking about or has the strength of purpose it pretends to.

Sadly, given Mitt Romney's various pro-stimulating utterances over the years - not to mention Paul Ryan's - and the Republican authorship of stuff like TARP and auto bailouts, the opposition is hardly in the position to make the case that Obama's interventions have lengthened the recession.

Romney was sharp to highlight Obama's dismal economic record at the Republican National Convention. Whether focusing exclusively on that is enough to win the governor the White House remains to be seen. But it sure isn't going to help the nation come 2013 if Romney can't articulate exactly what he would do differently than his immediate predecessors.