Presumptive Republican presidential nominee Mitt Romney escalated his attacks on President Barack Obama's welfare waivers Monday, suggesting that welfare recipients make up President Barack Obama's political "base."

In an interview with USA Today, Romney defended his much-criticized ads, which falsely accuse the president of removing the work requirement in welfare. He insisted that the spots were accurate and that Obama had pursued his policy as part of an electoral calculation.

"There's no question in my mind that the president's action was calculated to... shore up his base," Romney said, according to an extended quote that USA Today provided to The Huffington Post. "Weakening the work requirement in welfare is an enormous mistake."

The racial components of Romney's welfare ads have already been much discussed, and Romney's suggestion that welfare recipients are Obama's "base" seems likely to only further anger those who view the attack ads as divisive. Welfare recipients, in fact, would make up quite a small "base" -- there were only an average of 4,417,445 recipients of Temporary Assistance to Needy Families in 2011, according to the Department of Health and Human Services (HHS).

Asked about the quote, Romney spokeswoman Andrea Saul responded: "President Obama’s liberal base are the people who believe the same way he does: that government is the solution to everything."

Romney's charge stems from a July memo from HHS inviting states to apply for waivers "to allow states to test alternative and innovative strategies, policies, and procedures that are designed to improve employment outcomes for needy families." It did not end work requirements.

In fact, Romney was one of 29 Republican governors who signed a letter to HHS in 2005 asking Congress for even more expansive waivers to the work requirement.

Multiple independent fact-checkers have said that Romney's ads are false, but Romney maintains they are correct.

"Well, we believe it's accurate," Romney told USA Today, in a portion of the interview that was provided to The Huffington Post. "The Richmond Times-Dispatch also believes it's accurate. Heritage [Foundation] and others have written stories that say this guts the work requirement. . . . (It) opens the door to removing the serious work requirement that was in the bill."

Romney and his campaign have shown little willingness to back off the attack on Obama's welfare waivers. According to The New York Times, the former governor's aides believe that the attack "resonates with working-class voters who see government as doing nothing for them." Despite the ostensible absence of race in the attacks, racial attitudes can be a crucial predictor of whites' views on welfare -- and that seems to hold true for the ad. Brown University political scientist Michael Tesler analyzed data of those who saw Romney's ad and found that it primed views on "racial resentment," but did not affect other attitudes such as "party or ideological self-identification."

UPDATE: 12:49 p.m. -- Susan Page of USA Today sent the full transcript of Romney's quote to The Huffington Post.

Well, we believe it’s accurate. The Richmond Times-Dispatch also believes it’s accurate. Heritage and others have written stories that says this guts the work requirement in welfare. When the law was written the section requiring work – I say when it was written, when it was reauthorized -- the section requiring work, section 407, said you may not waive the provisions in this section, specifically, because the members of Congress in looking at this matter found that a number of states were calling all sorts of things were work that weren’t work. And so they said, you must be preparing for work, looking for work or actually working to qualify for this section. And the president has decided, through a statement to the states, we’re going to waive that anyway, despite the language of the bill. That opens the door to removing the serious work requirement that was in the bill. I disagree with that approach. There's no question in mind that the president’s action in this regard was calculated to build support for him among people he wants to have excited about his reelection, just as so many of the things he’s done were designed to try to shore up his base. And weakening the work requirement in welfare is an enormous mistake.

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