By Matt ViserĀ & Tracy Jan

LAS VEGAS Presidential candidate Mitt
Romney faced withering attacks from GOP debate rivals Tuesday night over the health care plan he spearheaded in Massachusetts his perceived proclivity for switching positions and his former lawn companys use of illegal immigrants to mow the lawn at his Belmont home four years ago.
Romney who along with businessman Herman Cain is considered the national frontrunner in the campaigning for the Republican nomination was placed in the center of the stage and it did not take long for Texas Governor Rick Perry and others to aim their barbs at him.
When Perry raised accusations that Romney had hired illegal immigrants the former Massachusetts governor -- who has largely been able to deflect criticism in previous debates -- became clearly irritated.
Are you just going to keep talking?" a red-faced Romney said at one point when Perry continued to interrupt him. You have a problem with allowing someone to finish speaking. I would suggest if you want to become president of the United States you have to let people finish speaking."
Romneys frustration turned to mocking.
This has been a tough couple of debates for Rick and I understand that" Romney said. And so youre going to get testy."
Romney faced similar charges when he ran for the GOP nomination in 2008 after the Globe reported that the company he hired for his landscaping Community Lawn Service was using illegal immigrants. He had fired the company in 2007 after the Globe inquired about the work.
The debate capped a fall season that has included near-weekly debates it was the fifth since Labor Day in an unsettled nominating contest that seems to have a new national front-runner each month. With voters expected to hit the polls within 90 days the tempers that flared illustrated the high stakes the sense that President Obama is vulnerable and the apparent animosity Romney and Perry have for one another.
For Cain it was a particularly important debate. The Georgia businessman has soared in the polls on the strength of his ebullient straightforward manner and his pitch for his 9-9-9 tax simplification policy. Yet he has been running his campaign on a shoestring and there has been little evidence he has the resources to mount a national effort.
His 9-9-9 plan which would remove the current federal tax code and replace it with a 9 percent tax on corporate income and sales taxes was roundly criticized. Several of his rivals particularly former House speaker Newt Gingrich and Romney prefaced their comments with praise for Cains audacity and perseverence in advancing the debate on taxes.
The criticism was led by Perry. The Texas governor who has fallen in the polls largely because of ineffective debate performances and his support for instate tuition discounts for illegal immigrants was far more animated in his attacks on Cain and Romney.
Herman I love you brother" said Perry. But let me tell you something. You dont need to have a big analysis to figure this thing out. Go to New Hampshire where they dont have a sales tax and youre fixing to give them one. Theyre not interested in 9-9-9."
Representative Ron Paul of Texas called the plan dangerous and regressive. Representative Michele Bachmann of Minnesota said it would give Congress a blank check to raise taxes. And Rick Santorum the former Pennsylvania senator criticized Cain for taking away tax breaks for families.
I like your chutzpah on this Herman" Romney said. But I have to tell you the analysis I did person by person return by return is that middle income people see higher taxes under your plan. If its lower for the middle class thats great. But thats not what I saw."
Cain said his tax plan would liberate the American people" from the current tax code which he characterized as a 10 million word mess." He dismissed criticisms as knee jerk reactions" and admonished critics for comparing apples to oranges -- to which Romney said in reference to having to pay a federal sales tax on top of state sales tax Im going to be getting a bushel basket that has apples and oranges in it because Im going to be paying both taxes."
Romney who has won praise for his demeanor and poise in previous debates made a rare tactical misstep early in the debate. The second round of questioning was presented by moderator Anderson Cooper as a chance for Romneys rivals to comment on his 59-point economic plan which Perry resisted instead concentrating on his own energy-exploration plan.
In response Romney gave only standard boilerplate support on his own economic plan considered the strength of his campaign and initiated discussion on health care considered by some his biggest vulnerability.
The rest of the round of discussion shifted to his Massachusetts plan being the foundation for Obamas national plan. Romney while continuing to defend the Bay State law while saying he would repeal the national plan was forced back on his heels.
You just dont have credibility Mitt when it comes to repealing ObamaCare" said Santorum adding that Romney did little to try to control spiraling health costs.
What you did with a top-down government-run program was focus on the problem of health care access" Santorum said. Youve blown a hole in the budget up there. And you authored in Obamacare which is going to blow a hole in the budget of this country."
Rick Im sorry you dont like it" Romney replied. The people of Massachusetts like it by about a 3 to 1 margin."
Theres a lot of big government behind RomneyCare" former House Speaker Newt Gingrich said.
The debate which aired live on CNN took place in a state that has been hammered by the economy. Nevada has the nations highest unemployment rate and the highest home foreclosure rate. More than a fourth of the states population is Hispanic so issues around immigration played a key role.
Former Utah Governor Jon Huntsman dropped out of the debate last week -- and is also threatening to boycott the Nevada caucuses altogether to protest the state GOPs decision to hold its caucuses on Jan. 14 complicating the primary calendar for New Hampshire. Huntsman instead will held a town hall meeting last night in Hopkinton N.H.
Nevada has risen in prominence during this years Republican presidential contest after the Republican National Committee deemed it one of the first four states to vote. But the spat over when the state will vote has threatened to overshadow the states political importance.
Several candidates besides Huntsman including Santorum Gingrich Cain and Bachmann have threatened to boycott the states caucuses if the issue is not resolved. Such a move could dilute the importance of the states vote and also stymie Romney. The former Massachusetts governor is the favorite in Nevada a state that he won in 2008 and one where many caucus-goers share his Mormon faith.
A new CNN/ORC International poll released yesterday had Cain and Romney in a virtual tie if the Republican nomination were held now. Those surveyed said Cain was more likeable and would best get the economy moving again.
But Romney was seen as the most likely to win the nomination and having the best chance at defeating President Obama.
Matt Viser can be reached at maviser@globe.com. Tracy Jan can be reached at tjan@globe.com.