Mitt Romney is best when he is counter-punching. When he was attacked by the White House for his New Hampshire ad, he came back swinging and showed some glee in doing it. Now that Gingrich is atop the polls, trying (weirdly) to attack Romney from the left on his Bain experience, the Romney camp is firing on all cylinders.

Romney is out with a new ad:

The message: Gingrich will sell out the right, just like he did when he cut the legs out from under House Republicans on the Ryan Medicare reform plan.

Romney also got a break today when Rep. Paul Ryan (R-Wis.), who has been biting his tongue and steadfastly refusing to endorse or mix it up, responded to Gingrich’s attack that Ryan’s Medicare reform plan amounted to “suicide”:

Ryan, in an interview with National Review Online, says that he disagrees with Gingrich, and urges Republicans to confront fiscal problems, irrespective of political risk. Worrying about electoral “suicide,” he says, is a disservice to voters, “who don’t want to be pandered to like children.”

“This is not the 1990s,” Ryan says. “The ‘Mediscare’ is not working and we should not back down from this fight.”

“Leaders don’t follow the polls, leaders change the polls,” Ryan says, adding, “Leaders need to go out and change things, speaking to people as adults.”

Ouch. Gingrich may find out (since he apparently does remember when it happened before) that attacking Ryan is a very dumb thing to do. Ryan is among the most respected Republicans and has become something of a rock star with the base for taking on Obama on the budget and entitlement reform.His comments will come as music to the ears of all the not-Newt candidates, who are trying to knock Gingrich down.

This is the same point — Gingrich is a menace to free-market capitalists and conservatives more generally — that Romney made in a Fox News interview, responding to Gingrich’s demand that he give back the Ban money:

“Well, unfortunately the Speaker is way off on that. In my enterprise, we had the occasion to help build tens of thousands of jobs. And he doesn’t understand the economy, if he doesn’t understand that sometimes businesses succeed and sometimes fail. The four enterprises I’ve led have all succeeded,” Romney said, adding, “To suggest that there is something un-American or something wrong about investing in enterprise that ultimately doesn’t succeed bespeaks an extraordinary lack of understanding of how the economy works.

“And by the way, should he return the money that he got from Freddie Mac? That follows his own comment. He said anyone who profited from Freddie Mac should give the money back. Well, he profited $1.6 million from an agency that helped bring down the entire economy; he ought to give it back,” Romney added.

The three themes that come together in these attacks aren’t hard to spot. Gingrich is erratic. Gingrich adopts leftist rhetoric and positions when it suits him, thereby harming conservatives. And he’s a lobbyist, not a Tea Party model.

It does appear that the attacks, which are coming from other opponents as well, are taking a toll. The Reuters/Ipsos national poll has him ahead by 10 points, while the Associated Press/GfK survey has his lead shrinking to 6 points.

It’s not clear that all of this will topple Gingrich from his first-place perch. But it does suggest that engaging Gingrich is helpful to his opponents. And in Romney’s case, it has put some spring in his step and allowed him to be on the side of those anti-Pelosi, pro-capitalist Republicans. Maybe Romney should have started earlier.