Much has been made of President Obama's convention bounce and subsequent flop for Republican nominee Mitt Romney, which continued last night when a new Fox News poll put him 5 points behind President Obama.

But what's more troubling for Romney in these polls is the fact that he's losing almost all ground on what has always been perceived as his major advantage — the economy. This week, in numerous polls, Obama is wiping out Romney's lead on handling the economy and jobs.

We saw it again last night in the Fox News poll. First, on the issue of handling the economy and creating jobs, the two candidates are tied, 46-46. That's a 3-point swing from last month and an even bigger swing from June, when Romney held a 7-point advantage.

The Fox News poll isn't alone:

These all collide with the perception that Romney can win the election as a referendum on Obama's job performance with the economy. The other economy-related poll questions don't paint a bright picture for Romney, either.

First, Romney's focus on the "Are you better off than four years ago?" question appears to be a wash, at best. Voters are evenly split on whether they're better off under Obama's tenure. Moreover, most voters say they are better off than one year ago.

And then there's this question from Fox: "Do you think Mitt Romney has a clear plan for improving the economy, or not?"

Just 42 percent said yes. And 49 percent said no.