COLUMBUS, Ohio - Mitt Romney came under fierce assault from his Republican primary opponents on Sunday as the campaign headed to the crucial 10-state slate of Super Tuesday contests, with Newt Gingrich accusing the former Massachusetts governor's campaign of displaying a "breathtaking scale of dishonesty.''
Romney, fresh from his Saturday night victory in the Washington caucuses - his fourth straight win - campaigned in several states and tried to cast his candidacy as being on a winning track. New polls show him virtually tied with Rick Santorum in Ohio and Tennessee, and the former Massachusetts governor rolled out more endorsements from leading conservatives as he sought to shore up support among those who most distrust him.
"What I have seen is a very hard-fought primary,'' House majority leader Eric Cantor said as he endorsed Romney on NBC's "Meet the Press.'' "And we have seen now that the central issue about the campaign now is the economy.''
Santorum said on Sunday that he hopes to do well enough on Super Tuesday to emerge as the one clear alternative to Romney. "This is a game of survival,'' he said while campaigning in Memphis.
But Gingrich, leading in the polls in his home state of Georgia, is also hoping to emerge as the anti-Romney candidate. He sought to inject his campaign with new momentum yesterday by dishing out some of his toughest rhetoric yet, saying that Romney is an inauthentic, lying politician. The assault highlighted divisions within the party that some Republicans fear will make it more difficult to defeat President Obama.
Gingrich, a 20-year congressman and former House speaker, called the former Massachusetts governor "the consummate insider'' and "the establishment candidate.''
"There's a breathtaking scale of dishonesty underlying the Romney campaign,'' Gingrich said on CBS's "Face the Nation.'' "Every time they ought to close the deal, the American people stop and say, 'Wait a second. There's something fundamentally false about his premise.' ''
"It's really sad. I mean, if he had just run as who he really is he might well get the nomination,'' Gingrich added. "And he would have gotten it authentically as the person he is, not the person he's pretending to be.''
Even as Gingrich said the party would unite behind whoever the nominee is, his comments reflected the type of vitriol that still exists within the Republican Party toward Romney, who has tried to convince the most conservative in the party to support him.
The charges came in the final hours before Super Tuesday, when 10 states will vote to distribute delegates in the biggest single-day haul of the nominating contest. No state is seen as more crucial than Ohio, which provides one of the best clues yet for who will be able to knit together the kind of general election constituency needed to effectively challenge an incumbent president.
A poll released on Sunday showed Santorum narrowly leading Romney in Ohio, with 34 percent of the vote to 32 percent. The NBC/Marist poll had a margin of error of 4 percentage points, making the race a toss-up. The Real Clear Politics consolidated poll, as of Sunday, had 34 percent for Santorum and 31 percent for Romney.
In recent polls, Santorum had a much more comfortable lead, but Romney seems to be benefiting from his Michigan win and an advantage in advertising dollars. As they have in state after state, Romney and the independent Super PAC supporting him have vastly outspent his rivals.
Still, in a sign of how bruising the Republican nominating contest has become, Obama is leading any of his potential opponents by double digits. Romney, who fares the best in the matchup, is 12 points behind, according to the NBC/Marist poll respondents.
While Romney concedes that he doesn't always bring the passionate flare to ignite the GOP base, it is the mundane but crucial organizational tasks that are giving him an edge on Tuesday.
Santorum and Gingrich failed to get on the ballot in Virginia, almost ensuring Romney will win all 46 delegates in the state. Santorum didn't submit the necessary delegate slate in several Ohio congressional districts, meaning even if he wins there he probably won't receive the votes at the convention.
Santorum said Sunday on Fox News that the delegates had to be filed in early December, while he was campaigning in Iowa and hovering at 2 percent in national polls, with limited resources. "We've done amazingly well for a campaign that early on didn't have a lot of resources to go out and do things,'' Santorum said.
Romney is leading the delegate count, with 203, more than double Santorum, his nearest opponent. In addition to Virginia, he's likely to win in Massachusetts, the state he governed for four years; in neighboring Vermont; and in Idaho, where many voters share his Mormon faith.
A new poll released on Sunday by the American Research Group indicated that Romney could also be competitive in Tennessee. The survey showed Santorum winning 35 percent among likely Republican primary voters, with Romney getting 31 percent. The margin of error was 4 percentage points.
Santorum is hoping to gain his first wins since Feb. 7, when he surprised the political world with a sweep of three states that brought fresh doubts over whether Romney could win the nomination. Santorum nearly pulled off another upset in Romney's native Michigan, but the former Massachusetts governor won the state and helped stem some of Santorum's momentum.
Ron Paul, who has an ardent following but has yet to win a nominating contest, was campaigning in Alaska on Sunday.
"Do I believe I can win? Yes,'' he said on "Face the Nation.'' "Do I believe the chances are slim? Yes, I do.''