Obama campaign mocks Romney use of Bill Clinton

President Barack Obama's re-election spokeswoman mocked the Mitt Romney campaign for using Bill Clinton in its latest ad, joking that the Republican standard-bearer must have run out of supporters in his own party.

"If that's the best validator they can find—someone who thinks President Obama is a far better choice on the economy and on other issues—perhaps his bench is a little shorter than we thought it was," campaign spokeswoman Jen Psaki told reporters aboard Air Force One.

"This isn't the first time that they have attempted to use President Clinton," she underlined. "It's interesting because President Clinton is not only a strong supporter of President Obama—he'll be speaking about him at the convention—but he has said time and time again that President Obama is the right person to lead the country forward, to help our economy continue to move forward."

Romney's campaign invoked Clinton in an ad attacking Obama's approach to welfare reform, an overhaul crafted by the former two-term Democratic president and his Republican foes in Congress in the 1990s over the objections of many liberal Democrats. But Clinton released a statement late Tuesday siding firmly with Obama and against the commercial.

"There is no more credible spokesman on this issue than President Clinton," White House spokesman Jay Carney said during the same briefing.

Clinton, who is popular with working-class white voters that Obama has at times struggled to reach, will formally put the incumbent's name in nomination at the party's convention in Charlotte, N.C.

After clashing with Team Obama frequently and often bitterly on behalf of Hillary Clinton in the 2008 Democratic primaries, Clinton has emerged as a potent surrogate for his wife's former rival. But things have not always gone smoothly: Republicans seized on ambiguous comments earlier this year in which Clinton seemed to break with Obama on tax policy. And, at a time when Obama has been hammering away at Romney's record as the head of private equity firm Bain Capital, Clinton praised the former Massachusetts governor's "sterling" business credentials.