In Las Vegas, Tuesday night's Republican presidential debate was arguably the hottest show on the Strip.
It was supposed to be a test for businessman Herman Cain, who has gone from nowheresville to competing for the title of front-runner. But Texas Gov. Rick Perry, whose debates and poll numbers have been lackluster, showed a combative side that had been missing up until now.
Cain, the former Godfather's Pizza executive, has become known for his down-to-earth eloquence and just one single policy proposal: the 9-9-9 plan. That's the percentage of tax he wants Americans to pay on personal income, corporate profits and purchases. Now that Cain is virtually tied for first with former Massachusetts Gov. Mitt Romney in the latest poll, just about every other candidate on stage took a turn explaining why they think 9-9-9 is really a big zero.
"If we give Congress a 9 percent sales tax, how long will it take a liberal president and a liberal Congress to run that up to maybe 90 percent? Who knows?" said Minnesota Rep. Michele Bachmann.
Former Pennsylvania Sen. Rick Santorum weighed in: "Herman's well-meaning, and I love his boldness and it's great, but the fact of the matter is, reports are now out that 84 percent of Americans would pay more taxes under his plan."
Cain didn't argue for his plan so much as repeat it — and tell everyone they were wrong.
"I invite every American to do their own math, because most of these are knee-jerk reactions," he said.
But Perry wasn't buying it.
"Herman, I love you brother, but let me tell you something — you don't have to have a big analysis to figure this thing out," the Texas governor said. "Go to New Hampshire and they don't have a sales tax and you're figuring to give them one. They're not interested in 9-9-9."
For the first time in the campaign, Perry looked like he was glad to be on the debate platform, ready to mix it up with his competitors. He seemed to be enjoying himself, especially when he was going after Romney, accusing him, for example, of hiring illegal immigrants as gardeners.
"The idea that you stand here before us and talk about that you're strong on immigration is on its face the height of hypocrisy," Perry said.
Romney had employed a landscaping company that was found to have undocumented workers on the payroll. He confronted the landscaper, and when the pattern persisted, the company was fired.
So Romney perhaps felt justified when he said, "I don't think I've ever hired an illegal in my life."
Perry tried to cut him off and the two candidates got into a verbal scrap, with Romney demanding, "Are you going to let me finish what I'm saying?" The audience, which seemed to have a large number of Romney supporters, began booing.
There were more free-for-alls like that one before the evening was out. The jeers didn't seem to bother Perry in the least, but he treaded more carefully when the subject of Romney's religion came up.
When asked to comment on the remarks of an evangelical pastor who supports Perry and who called Mormonism a cult and said Romney was not a Christian, Perry said America is a country with freedom of expression.
"That individual expressed an opinion. I didn't agree with it, Mitt, and I said so," Perry said.
For his part, Romney seemed to let it roll off his back. "You know, with regard to the disparaging comments about my faith, I've heard worse. So I'm not going to lose sleep over that," he said.
After the debate, which was broadcast by CNN and moderated by Anderson Cooper, Romney spokesman Eric Fehrnstrom said he thought Perry's aggressive behavior backfired.
"Rick Perry had a strategy coming into this debate to kill Mitt, and he ended up killing himself," Fehrnstrom said. "The reason I say that is because of the audience reaction. Every time Perry resorted to a personal attack or a cheap shot, the audience booed."
But Perry spokesman Ray Sullivan said he liked his candidate's performance and had no regrets.
"We feel like he forcefully defended his record and dominated tonight's debate. That's a win-win for us all around," Sullivan said. "Tonight was a very good night for us and gives us a lot to build on going forward."
The Republican candidates have debated five times in the past six weeks. The next confrontation isn't until early November, so they have some time to rest up, let the bruises heal and prepare their best shots.