“Every year they audit me, audit me, audit me,” an exasperated Donald Trump said at a primary debate in February. His personal federal income taxes, he claimed, had been audited by the Internal Revenue Service for more than a decade.

But the cause for his chagrin also offered Trump an escape hatch. He said he would not publicly release his returns until the audit was complete.

“I can’t do it until the audit is finished, obviously. And I think people would understand that,” he said.

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It’s a position Trump has clung to for months. But what is there to understand exactly?

There is no law prohibiting someone from making his own tax information public (audit or no audit), nor one compelling presidential candidates to release them. Yet every major party presidential candidate has since 1976.

Trump’s refusal to release his returns may buck precedent, but his non-disclosure goes even further. Trump won’t provide proof he’s actually under audit.

Taxpayers under audit receive a phone call or letter from the Internal Revenue Service informing them their returns are under review. Anyone notified by phone also receives the letter that says in part, “Your federal income tax return for the year shown above has been selected for examination. We examine tax returns to verify the correctness of income, deductions, exemptions, and credits.” Here’s a sample from the IRS website.

Some filers are asked for additional financial documents like canceled checks or receipts. The IRS uses “examination” and “audit” interchangeably.

Trump’s tax return could reveal unflattering information for someone who has built a reputation and presidential run heralding his extreme wealth. It would show his annual income, tax rate, and how much he gives to charity.

But the IRS notification letter is a different story -- it would not likely do any political damage to Trump’s candidacy. The form merely contains the taxpayer’s name, address, social security number (which could be redacted) and a generic reason for the audit.

Four emails to Trump’s campaign seeking this IRS letter yielded no reply. In response to another inquiry, spokeswoman Hope Hicks pointed to another letter - one written by Sheri Dillon and William Nelson, tax attorneys representing Trump.

Dillon and Nelson wrote Trump’s “inordinately large and complex” returns have been “under continuous examination” by the IRS since 2002. The returns from 2002-2008 had been “closed administratively,” but the examination, they wrote, from “2009 year and forward are ongoing.”

It does not specify which years’ returns after 2009 are being examined.

The letter also said entries in the 2002-2008 returns -- even though those audits are closed -- could impact the returns currently under an open examination. This likely means that Trump has so-called “carry-forwards” from those years that could affect his tax liability in 2009 and beyond. The New York Times over the weekend revealed that Trump’s personal tax returns declared a loss of $916 million in income in 1995, and that massive loss could be carried forward to lower or cancel out his income taxes for 18 years.

Trump told the Washington Post in May he would not release any returns from 2002 on – regardless of audit status - because “they’re all linked.”

While there’s no reason to doubt the veracity of his attorney’s letter, Dillon and Nelson did not respond to an emailed inquiry (nor provide any IRS documentation).

Their letter, dated March 7, 2016, does not specify if Trump’s 2015 returns are under audit. It is unlikely that his 2015 return would have been filed by early March, according to a tax expert, and even less likely that the IRS would have notified Trump of an audit by then.

Wednesday on CNN, Jason Miller, a communications advisor to Trump, was asked if he could produce the audit letter.

“Mr. Trump has made very clear that he’s under audit, and those paperworks (sic) will go back to the lawyers and the accountants--,” Miller said before trailing off.

“Well, we’re taking him at his word. Is there -- can you produce some evidence that he is, in fact, being audited?” anchor Alisyn Camerota asked.

Miller replied: “Well, I’ll leave that to the lawyers and the accountants as far as what exactly is public and what exactly is private.”

Last month, IRS commissioner John Koskinen appeared before the House Judiciary Committee.

“There’s no restriction by the IRS,” Koskinen testified, after being asked if there is any law that prevents a person from publicly disclosing an IRS audit notification.