More than a year ago, in February of 2015, Donald Trump—who was not yet running for president—said he would "certainly" release his personal tax returns. "I would release tax returns," he told conservative radio host Hugh Hewitt, reiterating later in the interview that, "I have no objection to certainly showing tax returns."

In January of this year, as Trump was leading in the GOP primary polls, he again said that the returns were forthcoming. "We're working on that now. I have big returns, as you know, and I have everything all approved and very beautiful and we'll be working that over in the next period of time," he said on MSNBC.

In May, after he had effectively locked up the nomination, he said once again that he planned to release them—though perhaps not until after the election. "So, the answer is, I'll release. Hopefully before the election I'll release," he said on Fox News. "And I'd like to release." The hold-up, he explained, was that he was under audit by the Internal Revenue Service.

Trump formally accepted the Republican party's nomination for president last week. And this morning, his campaign manager, Paul Manafort, confirmed what Trump's year-plus-long dodge on the matter has always implied: Donald Trump won't release his tax returns before the presidential election this November.

"Mr. Trump has said that his taxes are under audit and he will not be releasing them," Manafort said this morning.

This isn't a violation of any rule. But as with so much of Trump's campaign, it's a violation of norms and expectations. He will be the first major party nominee in more than 40 years to not make any returns public. There's no modern precedent for his refusal to release this information; instead, Trump is setting a precedent, paving the way for candidates of the future to avoid transparency.

There's lots of speculation about why, exactly, Trump won't release the information. Would it show financial connections to Russia? Would it reveal that he paid no taxes, or that he made very little money? Would it suggest that Trump is not nearly as rich as he says he is?

These sorts of guessing games, while interesting, don't get us far. But the refusal to release the returns is telling enough. It's more evidence that his word isn't worth a damn, and neither are his excuses.

Trump's vows to release his tax returns, like so many of his promises, were totally worthless. And his stated reason—that he is under audit by the IRS—doesn't hold up either.

There's no rule whatsoever prohibiting Trump from releasing returns, even in the midst of an audit, presuming that he is, in fact, being audited (and there's some question about whether this is even true). He could do so if he wanted.

Indeed, there's a precedent for a presidential candidate releasing his returns even as an audit is ongoing. In 1973, Richard Nixon was embroiled in a tax scandal over a charitable donation on his personal tax returns. As a result of the scandal, according to tax historian Joseph Thorndike, Nixon's taxes were scrutinized by the Joint Committee on Taxation, which found that he owed nearly half a million dollars more than he had paid. The IRS eventually agreed. Despite all this, Nixon still managed to make his tax returns public.

That's how shady Trump is: He makes Nixon look like a model of transparency and accountability.

(Correction: Nixon wasn't running for re-election in 1973! Apologies for the error.)