Mitt Romney has unveiled a new explanation for why he has refused to release more than two years of his income tax returns. The Republican presidential nominee told Parade magazine that the Mormon church keeps confidential the donations of its members. The trouble is, Romney already has shared one year of his generous giving in releasing his 2010 return. He has pledged to do so again before Oct. 15, the deadline his campaign has set for making public his 2011 return.

Then, there is the complication involving his father, George Romney, also generous to the church, who released a dozen years of his tax returns as part of running for president in 1968. Mitt Romney clearly has made a campaign calculation. He and his wife Ann both have argued that sharing additional returns would amount to providing “ammunition” to the Democratic opposition. They want to stay on message, reasoning, evidently, that persistent calls for more tax returns are far less distracting than the actual release would be.

Yet the calls promise to continue, as they should, Romney having an obligation, according Jon Huntsman, a Mormon, former Utah governor and once a Republican presidential candidate, to “be square with the American people.”

On Thursday, hundreds of pages of confidential documents from Bain Capital were published by Gawker.com. Analyses of the documents point to aggressive strategies for tax avoidance. James B. Stewart, a New York Times business columnist, looked at a decade of foreign income flowing to Romney (part of the 2010 return), and highlighted the use of the lucrative foreign tax credit.

Others have raised legitimate questions about Bain using a “total return equity swap,” a way of owning stock while giving the paper appearance of not owning, thus reducing your tax liability. Fair questions have been raised about Bain maneuvering to convert management fees into capital gains, again to lower the tax bill.

That isn’t to say Romney or Bain has done anything illegal, though the fees-to-capital gains trick carries the potential of real trouble. Romney insisted recently that he never has paid an effective rate of less than 13 percent in income taxes the past decade. Put aside the dismaying sight of a man of his wealth paying at such a low rate. As a presidential candidate, he has a duty to be forthcoming.

Most presidential candidates the past few decades have shared more than two years of their tax returns. Add that Romney has proposed further tax reductions that would favor wealthy households. He talks vaguely about ending an array of tax breaks. Five, six or seven years of tax returns may prove an education for the public. Certainly, he owes such a release to those in position to hire him for the job he wants.