By Z. Byron Wolf and Josiah Ryan

CNN

(CNN) -- Who knows who leaked two pages of Donald Trump's tax return.

But the leak, such as it is, does no harm to the President. It shows he actually paid income taxes -- at least in 2005. Whether the President had paid income taxes recently had actually been something of an open question.

The journalist that published two pages from Donald Trump's 2005 tax return says he doesn't know who provided the documents; he got them in the mail.

"Yes," Pulitzer Prize-winner David Cay Johnston replied when CNN anchor Poppy Harlow asked him if he thought the two pages, which show Trump paid $38 million in taxes on more than $150 million in income that year, could have been sent by the President himself.

"Donald has a long history of leaking things about himself and doing it indirectly and directly," Johnston told Harlow and Chris Cuomo. "So it's a possibility." He published the returns on his website DCReport.org

The White House has hit back hard against the publication, calling it illegal in a pre-emptive statement Tuesday night. Then President Trump himself weighed in Wednesday morning on Twitter, suggesting Johnston wasn't being forthright.

"Does anybody really believe that a reporter, who nobody ever heard of, 'went to his mailbox' and found my tax returns? @NBCNews FAKE NEWS!" tweeted the President.

The White House has not responded to a request for additional comment.

Leak leaves many questions about Trump's income sources

Trump didn't mention that The New York Times, when it reported Trump claimed $916 million in losses in 1995, which could have sheltered him from tax bills for many years, similarly received those more politically damaging documents in the mail.

The tax shelter created by those losses could create for some interesting return if Trump officially or the mysterious leaker were to provide return for other years. Additionally, the details of Trump's return would be instructive, too, answering questions about his charitable giving, if any, specifics about the losses he claimed -- $105 million in 2005 despite his tax bill, and more.

It is clear from evidence in lawsuits that there are years in which Trump paid no federal income taxes -- something he bragged about during a debate with Hillary Clinton.

"That makes me smart," he said on the debate stage, although he later clarified to CNN's Jim Acosta that he had paid income taxes.

Trump had long said he wouldn't release his income taxes because he is under some kind of long-standing federal audit. More recently, aides have said he might not release them at all. After all, he won the election.

But as Jeffrey Toobin pointed out on CNN Tuesday night, the questions about Trump's tax return have only grown more fascinating as questions have arisen about his campaign and business ties to Russia. Trump has denied current business connections to Russia, but he also denied the campaign aides had any contact with Russians in the lead-up to the campaign.

That sentiment was echoed by Edward Kleinbard, the Johnson Professor of Law and Business at USC Gould School of Law and a former chief of staff at the Joint Committee on Taxation.

"Only complete returns can resolve the questions swirling around his alleged financial obligations and sources of income, such as Russian oligarchs or other sovereign countries," Kleinbard told CNNMoney.

Convenient timing

News of the tax return and the fact that he did pay millions in taxes also provided a detour from questions about ties to Russia, the fragile health reform legislation he has pushed with House Speaker Paul Ryan, but which is in deep peril on Capitol Hill and scrutiny of his stunning claims that former President Obama wiretapped him during the campaign.

Another interesting element of the story is that Trump has listed large-scale tax reform as one of his major legislative priorities. Republicans are supposed to take up that issue after passing the first leg of their Obamacare repeal plan -- assuming they can pass it.

Repealing or fixing the Alternative Minimum Tax is sure to be on the table as Republicans go about their goal of lowering tax rates for most Americans. That'll be a more comfortable conversation for Trump to have with everyday Americans now that he can say he's paid the tax, too.

And it's a big reason whey Democrats, who have called repeatedly in the past for the release of Trump's rax returns, have warned the release of these two pages is a distraction from more important matters.

Correction: This post has been updated to correctly state the size of Trump's losses in 1995. It was $916 million.