The president charges his rival with memory loss as he tries to convince voters the Romney of the debates is not the real GOP nominee.

FAIRFAX, Virginia -- Mitt Romney's attempt to tack to the middle came so late in the presidential campaign that it caught President Obama somewhat off-guard. It's something most candidates do as soon as they're through their party's primary, but Romney didn't make much effort to strike a more moderate tone until presidential debates began this month. Suddenly, he was vowing not to cut rich people's taxes, embracing his work on health-care reform, and saying he'd expand rather than scale back Pell Grants for higher education.

On Friday, Obama finally came up with a snappy comeback to his rival's election-eve makeover. Romney, he charged, is suffering from "Romnesia."

He's forgetting what his own positions are, and he's betting that you will too. I mean he's changing up so much -- backtracking and sidestepping -- we've got to name this condition that he's going through. I think it's called "Romnesia." That's what it's called. I think that's what he's going through.

Now, I'm not a medical doctor but I do want to go over some of the symptoms with you because I want to make sure nobody else catches it.

If you say you're for equal pay for equal work, but you keep refusing to say whether or not you'd sign a bill that protects equal pay for equal work -- you might have Romnesia.

If you say women should have access to contraceptive care, but you support legislation that would let your employer deny you contraceptive care -- you might have a case of Romnesia.

If you say you'll protect a woman's right to choose, but you stand up at a primary debate and said that you'd be "delighted" to sign a law outlawing that right to choose in all cases -- man, you've definitely got Romnesia.

Now, this extends to other issues. If you say earlier in the year I'm going to give a tax cut to the top 1 percent and then in a debate you say, I don't know anything about giving tax cuts to rich folks -- you need to get a thermometer, take your temperature, because you've probably got Romnesia.

If you say that you're a champion of the coal industry when while you were governor you stood in front of a coal plant and said, this plant will kill you -- that's some Romnesia.

So -- I think you're beginning to be able to identify these symptoms. And if you come down with a case of Romnesia, and you can't seem to remember the policies that are still on your website, or the promises you've made over the six years you've been running for president, here's the good news: Obamacare covers pre-existing conditions.

We can fix you up. We've got a cure. We can make you well, Virginia. This is a curable disease.

Judging from the polls, the new version of Romney is one a lot of voters find appealing, so it's no wonder Obama is anxious to convince them it's not the real Romney. Will "Romnesia" be catchy enough to accomplish that? It's definitely catchy -- especially the Obamacare punch line, which had Obama himself cracking up a bit.

But it's also not the first time Obama has tried to play on his rival's name. When the president came up with "Romney Hood" a couple of months ago, his supporters loved it. But it didn't stick.