Speaking to a tea party audience on Wednesday, Rick Santorum mocked fellow Republican presidential candidate Mitt Romney and led the overwhelmingly friendly audience in a chorus of catcalls against President Barack Obama.

As Santorum harshly criticized the president on the economy and foreign policy during the speech in Tucson, audience members could be heard calling the president a "liar," "arrogant" - and repeatedly booing his name.

The candidate did not use those words himself. Instead, his words encouraged his audience.

For example, at one point, Santorum accused the president of appeasing "evil" around the world.

"Ronald Reagan was courageous enough to go out and speak about the forces of evil," the former Pennsylvania senator said.

He continued: "Our president refuses to call evil - evil. He refuses to even name it, refuses to confront it. He tries to appease and cajole it in an effort to reduce America's commitments around the world -- that if we just have paper or if we just try to make nice with those who are actively doing harm to America and its allies, that somehow or another that threat will go away or be ameliorated."

"And what we have found is that is simply, from history, it doesn't work."

On Tuesday, the former Pennsylvania said, "I believe in good and evil" in response to CNN questions about his 2008 comments that Satan had set his sights on the United States.

The previous comments raised eyebrows. Yet Santorum defended his words.

At another point during the Tucson speech, Santorum accused the president of trying to end core U.S. beliefs.

"Essentially we are going to have to hold together on some set of moral codes and principles," Santorum said. "And we are seeing very evidently what the president's moral codes and principles are about. We see a president who is systematically trying to crush the traditional Judeo-Christian principles in this country."

Such language directly appeals to Christian evangelicals and the conservative tea party movement - two groups Santorum is courting in the GOP race. Speaking just under an hour, the candidate promoted tea party ideals: adherence to the Constitution, lower taxes and less entitlement spending.

The candidate also addressed an issue of major concern to Arizona, one of four states that border Mexico.

"You have my pledge that we will secure this border," Santorum said. "We will deal with the issue of the drug violence and the cartels."

He also pledged, if elected president, to "deal with the national security threats to our country at the border and secure the border so that the people in Arizona can live in peace and prosperity just like every other state in the country."

The afternoon event was Santorum's only public appearance of the day ahead of the CNN/Arizona Republican Party Debate Wednesday evening. CNN's John King will host that debate - the last before Super Tuesday.

Meanwhile, Santorum appears to be increasingly wielding a double-edged sword: training as much fire against the president as he does against Romney.

On the same day the former Massachusetts governor played up his tax plan to revive the economy, Santorum mocked his rival.

"I just saw today that Governor Romney announced that he was going to be lowering the tax rates to - well, the tax rate I proposed," Santorum said.

"Welcome to the party, Governor. It's great to have you along."

And Santorum continued to draw contrasts between himself and his main rival.

"Look at the record versus the rhetoric of what you see of in many cases 'Johnny Come Latelys' to the conservative cause," the candidate said. "That's the decision you have to make here in Arizona. Who do you trust? Who is authentic? Who is believable?"

Romney's campaign responded with a statement linking Santorum to Obama.

"It's no surprise that Senator Santorum would try to associate himself with Governor Romney's conservative, pro-growth plan to cut taxes and grow the economy," Romney spokesman Ryan Williams said. "But there are crucial differences. First, Governor Romney's plan will not explode the deficit in the way that Senator Santorum's will. Second, Senator Santorum takes the exact same approach to tax policy as Barack Obama-he wants government to pick winners and losers."

Some national polls suggest that Santorum's double-edged slams may be helping him in the GOP race. However, in a new NBC News/Marist poll out Wednesday for Arizona, Romney holds a 16-point lead over Santorum.