The Justice Department lashes out at Democrats in a new legal opinion on Trump's taxes

Despite a lawful and orderly request from Congress to hand over President Donald Trump's tax returns, the Treasury Department has steadfastly refused to do so, in clear violation of the law that says the secretary "shall" follow any such directive.

The legal justification for this move has been transparently partisan (and indeed, personal) from the beginning — the administration is simply trying to protect the president. But on Friday, late in the afternoon, the Justice Department released an opinion purporting to justify Treasury Secretary Steve Mnuchin's disobedience.

To support the aggressive posture, the opinion, signed by the Office of Legal Counsel's Assistant Attorney General Steven Engel, essentially attacked Democrats, saying that Congress's stated reasons for requesting the returns "were pretextual and that its true aim was to make the President’s tax returns public."

In other words, it accused House Ways and Means Committee Chair Richard Neal (D-MA) of lying. When he had requested the returns, he has said they were for the purpose of reviewing the policy of automatic IRS audits of presidents.

Mnuchin "quite reasonably, concluded that Chairman Neal had not articulated the real reason for his request," the opinion said.

But it shouldn't really matter anyway, because the law doesn't say that Neal needs a legitimate purpose to obtain someone's tax returns. It simply gives him the power to request the returns and says the department "shall" turn them over. It's not ambiguous at all.

Still, the OLC opinion claimed that constitutionally, Congress can't force the administration to expose confidential information without a legislative purpose.

However, even if the dubious claim about this constitutional limitation on a duly enacted law were correct, it's simply not true that there's no legislative purpose to having either the Ways and Means Committee review the returns or for them to be made public. Congress might want to consider a law that would make any presidential candidate release his or her taxes. Or it might want to tighten up conflict of interest rules surrounding the president. Having Trump's taxes returns — and indeed, having them available publicly — would serve a legitimate legislative interest in these and other possible scenarios.

And regardless, the administration's claim that it has standing to review whether Congress's reasons for taking a certain course of action are legitimate flies in the face of its own legal arguments in other cases. In both the travel ban case and the citizenship Census question case, both of which went before the Supreme Court, the administration argued that its own patently pretextual reasons for taking these actions were irrelevant, and all that mattered was that the executive branch had the power to act as it did. So when it comes to the executive branch, the administration says its true motives don't matter; in the case of Congress, however, officials think they can disobey lawmaker's lawful demands if they're made with bad intentions.

In the travel ban and citizenship question cases, the arguments were highly dubious, given the clearly nefarious and discriminatory purposes these actions served. But there's no greater principle at stake in keeping Trump's tax returns private. There's simply a government doing its best to protect the leader — no matter the cost to law and constitutional order.

The opinion does have an odd response to these arguments. It acknowledges that the courts likely would not second-guess Congress's motives for requesting for the tax returns, but it still holds that is appropriate for Mnuchin to do so, given that the executive branch is responsive to the people. But this seems to suggest that, if Neal were to sue Mnuchin or the administration to comply with the directive, the courts would likely side with Congress.