Should the American people be entitled to as full an account of Paul Ryan’s taxes as the Romney campaign? New information about the vice-presidential selection process may revive interest in the issue as a flashpoint in the presidential campaign.

As part of its vetting, the Romney campaign required at least some of the candidates on the short list—including the eventual winner of the GOP veepstakes, Ryan—to submit fully 10 years of tax returns, according to a knowledgeable source.

The requirement was consistent with the past practices of both Republican and Democratic campaigns. Indeed, in 2008, Mitt Romney turned over 23 years of taxes to John Mccain’s campaign when he was under consideration to be the Arizona senator’s running mate.

But this year, the vetting of tax returns has had particular political resonance because of Romney’s refusal to release more than two years of his own tax filings. The Obama campaign has waged a withering assault on Romney for his failure to be more transparent about his personal finances, part of a larger narrative seeking to portray the Republican nominee as a privileged plutocrat who has been able to mine the tax code for loopholes and other tricks unavailable to average middle—class Americans. For months, Chicago and its allies have hammered Romney on taxes, suggesting he must be hiding something.

In response to questions about the 10-year requirement, Romney campaign press secretary Andrea Saul declined comment. “We do not discuss the VP selection process,” she wrote in an email.

But the revelation that Romney aides demanded that its veep candidates be more forthcoming with their own campaign than with the American public drew predictable scorn from Team Obama. “Mitt Romney needs to answer one question: if he needed ten years of returns to decide on a vice presidential candidate, don’t the American people need the same to make their choice for president?” asked Ben LaBolt, a spokesman for the Obama campaign.

With its populist bent and emphasis on economic inequality, the Obama campaign believes its relentless focus on the tax issue has paid high political dividends. The polls seem to back that up. A USA Today/Gallup poll earlier this summer indicated that 56 percent of Americans believe Romney should be more forthcoming with his tax information.

Leading the double-barreled attack on Romney’s supposed secrecy and privilege, often via Twitter, has been David Axelrod, Obama’s senior campaign adviser. As media attention began to focus on Romney’s search for a vice presidential candidate, Axelrod found a new way to press the tax issue: “Wonder how many years of back income tax returns Team Romney is asking for their VP candidates,” Axelrod asked in a Tweet in July. “Will their Veep release more than Mitt?”

Axelrod got his answer the day after Romney selected Ryan to be his vice presidential candidate. In an interview on 60 Minutes, Ryan told CBS’s Bob Schieffer that like Romney, he would release no more than two years of tax returns. When asked during the interview how many years of taxes he’d submitted to campaign vetters, he would only say “several.” That was the same answer given to reporters by Beth Myers, a top Romney adviser who led the candidate’s vice-presidential search. In media interviews after the Ryan announcement, the veep runners-up were vague about the number of tax releases they submitted. Former Minnesota Gov. Tim Pawlenty used the same “several” formulation as Myers, as well as characterizing the number as “a bunch.”

In the past, Romney advisers, including Ryan, have dismissed the tax issue as a political sideshow that is not high on the minds of voters. Romney has defended his decision not to release more information on his taxes, noting that he has done everything that is “required by law.” Moreover, Romney officials have argued that his position is in line with other presidential candidates including Sen. John McCain who released two years in 2008. That same year, then-candidate Barack Obama released seven years of tax returns. When Romney’s father, George Romney, ran for president in 1968, he released 12 years of returns.

When Romney has given the public a peek at his finances, he has invited charges that he, the wealthiest American to ever run for president, has paid far lower rates than most average taxpayers. Romney shelled out an effective rate of 13.8 percent in taxes on an income of $21.7 million in 2010. The candidate has not yet released his returns for 2011, but he has stated that he expected to pay a rate of 15.4 percent on income of $20.9 million. Romney earned most of his fortune at Bain Capital and as an executive of an investment firm was able to take advantage of lower tax rates through a loophole known as “carried interest.”

According to one Romney campaign adviser, there had been considerable debate earlier this summer about releasing more of the candidate’s taxes. In the end, those in favor of more transparency were overruled. The concern was not that Romney had skirted tax laws in any way; rather, it was that his taxes were so voluminous and complicated and involved so many investments and shelters —including offshore accounts in places like the Bahamas and the Caymen Islands—that the campaign would be handing the Obama camp free ammo.

One reason Romney has publicly cited for not making his taxes public is his reluctance to reveal how much he and his wife, Ann, have tithed to the Mormon Church. In an interview with Parade magazine, Romney said that his religious contributions are “a very personal thing between ourselves and our commitment to our God and to our church.”

In August, Obama campaign chief Jim Messina, suggested a compromise of sorts in the ongoing campaign war over Romney’s taxes. If Romney agreed to release a total of five years of returns, Chicago would declare a cease-fire and stop calling for more years of taxes. The Romney campaign rejected the offer.