MESA, Arizona (CNN) -- Mitt Romney and Rick Santorum mixed it up over their records on the debt, taxes and earmarks Wednesday night in the first Republican presidential debate in almost a month, and the first before three contests in the next 10 days followed by the Super Tuesday primaries and caucuses on March 6.
Answering a question from the audience on how to bring down the nation's debt, the former Massachusetts governor attacked Santorum's record when he was representing Pennsylvania in the Senate.
"Voting for the debt ceiling five different times without voting for compensating cuts," said Romney, describing Santorum as a big spender in Congress. "Voting to fund Planned Parenthood, voting to expand the Department of Education. During his term in the Senate spending grew by some 80% of the federal government."
Santorum, who surged to the top of state and national polling after sweeping the February 7 contests in Colorado, Minnesota and Missouri, was sitting center stage next to Romney and was quick to fire back.
"When you look at my record of never having raised taxes -- Gov. Romney raised several hundred million dollars in taxes and fees in Massachusetts. I never voted to raise taxes," Santorum said. "Governor Romney even today suggested raising taxes on the top 1%, adopting the Occupy Wall Street rhetoric. I'm not going to adopt that rhetoric."
The candidates hotly confronted each other in a lengthy and contentious argument over the arcane congressional process of earmarking.
"Congress has a role to play when it comes to appropriating money," Santorum declared in a full-throated detailed defense of the process -- one he said Romney had taken advantage of when he requested funds for the 2002 Olympic Games in Utah.
"I didn't follow all of that," Romney cracked after Santorum finished speaking. "But I can tell you this: I would put a ban on earmarks. I think it opens the door to excessive spending."
Santorum did not back down, telling Romney: "You don't know what you're talking about."
The two were seated next to each other at a table, flanked by Texas Rep. Ron Paul and former House Speaker Newt Gingrich. While they directed their attacks in each other's directions, their eyes rarely met.
While listening to Santorum's criticism, Romney shook his head or looked slightly to the side with a pained expression on his face. Santorum raised his eyebrows at Romney's attacks at him and looked off to the side as if he was running Romney's words through his mind.
Meanwhile, at several points Gingrich was captured chuckling at the other candidates' statements. While Romney and Santorum grew heated at times, Paul deflated the tension a bit when asked why he had labeled Santorum a fake in a television ad that attacked the former senator's conservative credentials.
"Because he's a fake," Paul said.
That line drew cheers, laughter and boos, before Santorum assured moderator John King that he was real.
"Congratulations," Paul responded.
A question on contraception gave Gingrich the opportunity to attack moderator John King, and a chance for agreement between Santorum and Romney. When King related a viewer's question on whether the candidates believed in birth control, Gingrich took immediate offense.
"You did not once in the 2008 campaign, not once did anybody in the elite media ask why Barack Obama voted in favor of legalizing infanticide. OK? So let's be clear here," Gingrich said, which brought applause from the audience. "If we're going to have a debate about who the extremist is on these issues, it is President Obama who, as a state senator, voted to protect doctors who killed babies who survived the abortion. It is not the Republicans."
However, Santorum and Romney did reach general agreement on the budding controversy over the issue, as both bemoaned the number of American children born out of wedlock.
"How can the country survive if children are being raised in homes where it's so much harder to succeed economically?" Santorum asked, but added he was speaking ideologically rather than advocating government intervention.
"Just because I'm talking about it doesn't mean I want a government program to fix it," he said.
Romney suggested the president should be "willing to say" the best opportunity a parent could give his child is a mother and a father.
Paul, a former obstetrician, said government should not insert itself into a debate over contraception. But, likening a user of birth control to a gun owner, Paul said the problem was not the contraception pill but the "immorality" of society.
"I think it's sort of like the argument -- conservatives use the argument all the time about guns. Guns don't kill, criminals kill," Paul said. "So, in a way, it's the morality of society that we have to deal with. The pill is there and, you know, it contributes, maybe, but the pills can't be blamed for the immorality of our society."
Asked to use one word to describe themselves, Paul proudly replied, "consistent."
Santorum's word was "courage," and Romney's was "resolute."
The crumudgeonly Gingrich got a laugh when he described himself as "cheerful."
The debate, hosted by CNN and the Republican Party of Arizona at the Mesa Arts Center, is the last time the candidates will share a stage before primaries in Arizona and Michigan on Tuesday, before Washington state holds a contest on March 3, and before 10 more states hold primaries or caucuses on Super Tuesday on March 6. And no more debates are currently scheduled. CNN canceled a debate in advance of Super Tuesday after Romney, Santorum and Paul pulled out.
The four last met on January 26 before the Florida primary. Romney went on to win big there and in Nevada, while Gingrich, who had just scored an impressive victory in South Carolina, faded fast. Santorum, once a long shot, tops national polling and is neck-and-neck with Romney in the latest surveys in Arizona and Michigan.