Romney Tax Return Debate Intensifies The Obama campaign sought to keep the pressure on Mitt Romney and his undisclosed tax returns for another day, releasing a cheeky video and dispatching the vice president to pound the Republican candidate on his past. The new video , accompanied by a ticking clock and a Klezmer-like clarinet, says Romney "is defying calls to release more than one year's worth of tax returns." Vice President Biden, meanwhile, made an allusion to Arizona's controversial immigration law that was mostly struck down by the Supreme Court as he told Hispanics, "Mitt Romney wants you to show your papers, but he won't show us his." Biden said there are "so many questions" raised by Romney's refusal to disclose his tax returns beyond one year. The debate began with supporters of President Obama demanding Romney disclose more of his financial background after media reports scrutinized a recently disclosed company he owned in Bermuda. "What's important is if you are running for president is that the American people know who you are and what you've done and that you're an open book," Obama told an ABC affiliate reporter. And that's been true of every presidential candidate dating all the way back to Mitt Romney's father. Romney's father, George Romney, disclosed 12 years of his tax returns in his failed 1968 White House bid, a precedent that Democrats have cited gleefully to accuse the Mitt Romney of hypocrisy. Romney responded in his own interview but indicated that he didn't plan on making more financial information available. He said there was "nothing hidden" in his returns. I don't even know where they are," he said. The latest Obama video may be an attempt to direct the summertime political conversation toward Romney's past rather than the struggling economy. A handful of high-profile Obama stand-ins, including Dick Durbin and Robert Gibbs, sat at the Sunday show tables to demand that Romney release his returns. They claimed that Romney loves Swiss banks but not the American dollar, and questioned why he failed to disclose ownership of a company in Bermuda. A surrogate for Romney, former Mississippi Gov. Haley Barbour, gave Democrats more ammo last night when CNN's Wolf Blitzer asked him whether Romney should disclose more returns. "I would," Barbour replied â which is the sound bite Democrats grabbed, despite the rest of Barbour's answer: "But should it be an issue in a campaign? I don't think it amounts to diddly.