WASHINGTON (CBSDC/AP) — Rick Santorum, showing signs of fatigue and frustration while grasping for strategies to right his unsteady White House bid, is trying to derail Republican front-runner Mitt Romney using any means available — even contradictory messages.

Santorum has called Romney “the worst Republican in the country” to challenge President Barack Obama, but in a subsequent interview he said he would consider serving as Romney’s running mate. He is not letting pass a vulgar fight with The New York Times while betting big on the health care debate, which his campaign says is intensifying at the perfect time to resurrect his fading candidacy.

“This is the most important issue in this election,” Santorum declared outside the Supreme Court on Monday while attorneys inside debated the constitutionality of the president’s health care law. “There’s one candidate who’s uniquely disqualified to make the case. That’s the reason I’m here and he’s not.”

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Seizing on the health care debate as Romney focuses on the nation’s economy, Santorum is fueling tea partyers’ lingering skepticism about the former Massachusetts governor, who signed into law a state-based health care program that helped inspire Obama’s plan. He dismisses Romney’s broadening support as the product of political elites, while pitching himself as an up-from-his-bootstraps candidate who came from “public housing” — a misleading claim that offers a stark contrast with Romney’s life of wealth and privilege.

In spite of Santorum’s loosely plotted uphill strategy, a growing number of establishment-minded Republicans are coalescing around Romney. On Monday, GOP House Whip Kevin McCarthy of California became the latest member of the party’s leadership in Congress to sign on. Romney remains on pace to capture the nomination in June.

The challenge seems to push Santorum to fight harder.

“He’s the worst candidate to go against Barack Obama on the most important issue of the day,” Santorum said Monday, highlighting the Massachusetts health care law Romney signed in 2006. It requires all Massachusetts residents to purchase insurance, the same “individual mandate” in question in Obama’s law.

Asked in a separate interview if he’d consider serving as vice president under Romney, he said, “Of course.”

“I’ll do whatever is necessary to help our country,” he told the Christian Broadcasting Network.

Struggling to settle on a consistent message, Santorum turned to social issues as part of a throw-it-all-out-there approach in recent days, hoping to find something that sticks with Republican voters.

“Gay marriage went into effect under Gov. Romney. Fifty-dollar abortions went into effect under Gov. Romney, and free abortions for low-income people under Romney,” Santorum said in Sheboygan, Wis.

The campaign’s new health care offensive, punctuated by Santorum’s appearance outside the Supreme Court, is backed by a series of web videos featuring Massachusetts residents criticizing that state’s health care plan. The videos, filmed by Santorum’s campaign last week, are set to be released this week.

The vast majority of Massachusetts voters, however, support the health care plan, according to recent polling.

Santorum also is highlighting his status as a working-man’s alternative to Romney, who amassed a personal fortune in the business world. The former senator’s recent schedule has featured guns, golf and bowling.

“From 50 feet with a 1911 Colt revolver, 14 shots, 14 on the target,” Santorum told voters last weekend. “I’m not bragging. Just the facts, ma’am. Just the facts.”

He bowled three consecutive strikes in borrowed bowling shoes. The next day, he followed up with another bowling alley visit. He bristled when asked to talk about the race.

“No, I’m sorry. No. It’s a bowling alley,” he said as he changed back into his cowboy boots.

Santorum’s mood has been more caustic than usual. He used profanity when responding to a New York Times reporter who asked him to clarify his assertion that Romney is the worst Republican to run for president.

“Would you guys stop distorting what I’m saying?” Santorum challenged the reporter after a rally Sunday. “Quit distorting our words. If I see it, it’s bulls—. C’mon, man. What are you doing?”

On Monday, Santorum didn’t back down from the angry outburst.

“I don’t regret taking on a New York Times reporter who was out of line,” he said as his campaign looked to turn the incident into a fundraising appeal. “If you’re a conservative and you haven’t taken on a New York Times reporter, you’re not worth your salt as far as I’m concerned.”

His latest biographical sales pitch raises some questions. He introduced himself in Sheboygan “as someone who grew up in Western Pennsylvania, in a steel town, a manufacturing town. … I grew up in public housing on the VA post.”

But he did not grow up in a public housing project, as the statement seems to suggest. His parents were employed by the Veterans Administration.

“My parents were both working there, so we were able to get post housing. My mom was an administrative nurse so they wanted her close by. … My dad was head of the psychology department,” he later clarified. “They were nice little apartments but, you know, they were small.”

Santorum adviser Hogan Gidley conceded that the campaign was at a critical point, but he suggested the Supreme Court case would help gets things back on track.

“This is obviously an important day for him and the campaign,” Gidley said outside the Supreme Court. “It’s perfect timing.”

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