Yesterday, former IRS Commissioner Fred Goldberg (who held top tax positions in the administrations of both Ronald Reagan and George H.W. Bush) urged Donald Trump to release at least the Form 1040 and Schedule A of his recent tax returns.  It increasingly appears that Trump won’t. But he should.

Trump has argued that he cannot make his returns public while they are being audited by the IRS. But the IRS now audits, automatically, the president’s and vice president’s return annually. Nonetheless, the president and vice-president voluntarily release their returns to the public. 

Trump’s excuses raise new questions. Last weekend, Trump’s new campaign manager, Kellyanne Conway, said Trump should keep his returns confidential because his audit is ”a serious matter.”  But, if Mr. Trump’s audit is a serious matter, we need to understand why to assess his qualification for the presidency.

True, Trump’s disclosure of his tax returns might intrude on his personal and commercial privacy. And with an audit pending, citizen auditors might provide the IRS insights that the professional auditors at the IRS overlooked (although the IRS is pretty effective at auditing high net worth individuals).

But Trump is no longer merely a businessman.  He has chosen to become a candidate for president. The public’s interest now outweighs his privacy concerns. During a campaign, tax disclosures help the public evaluate a candidate’s: 

• Finances. Is Trump truly a successful business person? Does he give generously to charity as he claims?  
• Conflicts. Would Trump’s tax proposals provide undue benefit for his personal interests? (He says he’d pay more, which seems unlikely, but it’s impossible to know for certain without seeing his tax return.)
• Honesty. Did Trump lower his taxes through legal tax avoidance, or illegal tax evasion? 

Trump asserts:  “There’s nothing to learn from them.”  But we would quickly learn a lot, including the bottom line:  his effective tax rate.  Of course, his tax returns are complicated:  He operates his business through more than 500 LLCs.  But there are plenty of experts who can help unravel the returns and explain the issues they raise, just as we recently assessed Clinton’s return.  Or how we explained “carried interest,” which was spotlighted by Mitt Romney’s tax return in the last election.                                               

Finally, if Trump will not release his tax returns now, will he do so after the election? President Nixon first released his taxes to quiet the public clamor over his reportedly low taxes (and invited the JCT to audit them after the IRS, reportedly, gave him a pass).  President Nixon famously explained “People have got to know whether or not their president is a crook.”  And from Nixon on, every president has voluntarily released his returns to the public—with the prospect of an audit pending.

Candidate Trump should follow the precedent set by every major party presidential candidate—and president--since Nixon and release his tax returns.