On Fox News, The Christian Science Monitor's Liz Marlantes explains why Obama's "you didn't build that" line is so politically damaging.
"I think this is the most effective line of attack the Romney campaign has had to date against Obama, and I think the reason that it's been so effective -- at least so far -- we see the White House is spooked about this.... Anytime the president has to say 'Of course, I believe Americans build their own business', that's not a good sign, obviously.
... even in context, the way it came out is it did seem to reflect a certain dismissiveness of business, and I think that is the weakest spot for this president in this campaign, so far."
As she later says, the "dismissiveness" toward business resonates with a lot of voters because it's a reflection of the "populist rhetoric" he's been deploying at nearly every rally.