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As Rick Santorum fights off efforts to label him extreme or "ultraconservative" for discussing faith and family on the campaign trail, the White House is taking a new tack against the Republican candidate and his presidential primary rival Mitt Romney -- accusing them both of driving up the deficit in their budget proposals.

In a memo on the "deficit-exploding budget and tax plans" by Romney and Santorum, Obama campaign Policy Director James Kvaal argues that while both candidates "champion spending cuts deep enough to cut taxes and balance the budget," they have, in fact, "proposed irresponsible and reckless tax plans that would drive up the deficit by trillions of dollars."

Saying their claims to balance the budget through spending cuts "are completely unrealistic," Kvaal argues that Romney's plan "would increase the deficit by at least $175 billion a year." That's in contrast to the president's plan released last week that doesn't see less than $600 billion in deficits for nine of the next 10 years.

"In total, Romney's tax plan would increase the deficit by $188 billion in 2016. The tax cuts are worth $146,000 a year to individuals earning more than $1 million a year. A typical middle-class family with children would actually pay $34 more," Kvaal wrote.

"Romney's budget would require cutting all non-defense spending by nearly 25 percent in 2016, according to the Center on Budget and Policy Priorities, and by 48 percent if Social Security and Medicare are spared. Santorum's claims are even less realistic," he continued.

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The Obama team's focus on both candidates suggests a shift in approach as Santorum gains nationally on Romney in polls ahead of the Arizona and Michigan primaries next Tuesday. The two candidates, as well as Newt Gingrich and Ron Paul, are expected to debate Wednesday night in Arizona. The votes in those two states are followed by Super Tuesday on March 6.

But the redirect toward economic issues come after days of sniping over Santorum's comments about Obama's energy policy, in which Santorum referenced the "phony theology" of radical environmentalists that he says Obama has embraced.

While the language used by Santorum is similar to that long purveyed by conservatives to label believers of global warming and other environmentalist movements as wing-nuts, the president's campaign called it an attack on Obama's Christian faith and said Santorum was "over the line."

On Monday, Santorum defended his remarks, saying that he's being attacked because he has moral values, not because he wants to impose them on anyone else.

"This makes it, you know, really a war on people of faith, particularly the Catholic faith, which again, I mean, it's very clear what the Obama administration is doing on that front," Santorum told Fox News. "For them to continually distort -- this is the kind of stuff that I think is actually, I think, one of the reasons we're doing well in the polls because people see it for what it is. They see a national media trying to destroy conservatives."

A Real Clear Politics average of polling shows Santorum is up in the polls, with 33.8 percent on average compared to Romney's 28 percent.

University of Virginia Center for Politics Director Larry Sabato said that Santorum winning three contests in early February pushed the headlines toward him, but his success isn't based just on buzz.

The way he speaks "is coming across as authentic," Sabato told Fox News. "He's very blunt, he's very forthright. He speaks as though he doesn't care about the political consequences."

But Santorum is walking a fine line. While he tries to focus on topics like Iran, budgets and energy policy, he has also questioned the usefulness of public schools, criticized prenatal testing and doubted whether women are physically able to keep up in combat.

That contrasts sharply with Romney, who has avoided social issues for the most part, and has been accused of not being passionate enough or conveying a reason for his being in the race. Instead, the former Massachusetts governor sells himself as the efficient CEO who will fix the economy.

A Mormon, Romney speaks about ensuring "religious liberty" and preventing a contraception mandate being imposed by the Obama administration on insurers, including those morally opposed to birth control, but his target audience is largely fiscal hawks.

"One of the people I'm running against, Senator Santorum, goes to Washington, calls himself a budget hawk then, after he's been there a while, says he's no longer a budget hawk. Well, I am a budget hawk," Romney said Monday.

"When Republicans go to Washington and spend like Democrats, you're going to have a lot of spending, and that's what we've seen over the last several years," Romney added.

With the primary race unlikely to wrap up soon, the two candidates offer a stark choice to represent the GOP in the November election against Obama. Romney maintains a massive organizational and fundraising advantage over all his rivals, while Santorum gets to the social soul of the conservative wing of the party.

A pro-Santorum PAC, the Red, White & Blue Fund, announced Tuesday it's all-in in Michigan, as Romney closes the gap in his home state. The super PAC is pouring $600,000 into Michigan for a statewide ad buy in the week ahead of the Republican presidential primary, a sum that the Romney team could easily match and best.