CNN  — 

President Donald Trump has been consistent about very few things during his relatively-short political life. But on one front he has been adamant: He will not release any of his past tax returns.

That position became slightly less tenable on Tuesday when The Washington Post reported on the existence of a 10-page draft memo from the Internal Revenue Service that makes clear the administration has no leeway when it comes to complying with a request for Trump’s returns from House Ways and Means Chairman Richard Neal, a Massachusetts Democrat.

The memo says that the turnover of Trump’s tax returns “is mandatory, requiring the Secretary (of the Treasury) to disclose returns, and return information, requested by the tax-writing Chairs” and adds that the IRS statute “does not allow the Secretary to exercise discretion in disclosing the information provided the statutory conditions are met.”

That assertion runs directly counter to Treasury Secretary Steve Mnuchin’s recent refusal to comply with a 1924 statute that says he “shall furnish” any individual American citizen’s tax returns to the heads of the House and/or Senate tax-writing committees. Mnuchin denied Neal’s request by citing the fact that he found no legitimate legislative purpose for the Ways and Means chairman to ask for the returns. In a letter to Neal earlier this month, Mnuchin wrote that he and the Treasury Department’s lawyers believe that “the Committee’s request lacks a legitimate legislative purpose.”

This memo, which was prepared by the IRS last fall, badly undercuts that argument. It clearly states that Mnuchin has zero discretion in the matter under the law; if Neal asks, Mnuchin needs to comply.

To be clear: This memo doesn’t mean that Mnuchin – and Trump – will suddenly reverse course and turn over the returns. Trump made a decision in the early days of his 2016 presidential campaign that whatever was in the returns was more problematic for him than the flack he would take over not releasing them. He’s not suddenly going to reverse that position.

But, what the memo – or, more accurately, the Post’s reporting of the memo’s existence – does is provide a major hurdle for the administration in the pending legal fight over the 1924 statute. Neal has made clear that he believes he has exercised all of the legislative options to get the returns and will now turn to the courts. “I think if both sides have made up their minds, better to move it to the next branch of government, the judiciary,” he told CNN’s Lauren Fox last week.

In that legal fight, the Trump administration now no longer can claim a fully united front. Sure, Mnuchin can say Treasury’s lawyers advised him that he has the ability to turn down a request for Trump’s tax returns if there is no “legitimate legislative purpose.” But the memo – which comes from the agency specifically tasked with handling the tax returns of Americans – directly contradicts that view. And it’s not a memo that Neal and his fellow House Democrats put together. It’s a memo from the damn IRS!

None of the above means that Neal is certain to prevail. The way a little-known 1924 statute is interpreted by a judge is a very difficult thing to game out. But it’s very hard to see how the existence of this IRS memo makes the administration’s case anything but tougher.

Which means that maybe – yes, maybe – we might actually see Trump’s tax returns.