White House counsel Donald McGahn, center, in September 2018 in Washington. (Win McNamee/Getty Images)
Opinion writer

President Trump’s lawyers now generate a nonstop stream of frivolous defenses in his all-out assault on Congress. On Monday, they made the ludicrous claim that former White House counsel Donald McGahn, who provided evidence to special counsel Robert S. Mueller III that wound up in the redacted Mueller report, cannot come tell Congress and the American people what he told Mueller.

The Post reports on the decision to assert “immunity” to prevent McGahn’s testimony:

The 15-page legal opinion written by Assistant Attorney General Steven A. Engel argues McGahn cannot be compelled to testify before the committee, based on past Justice Department legal opinions regarding the president’s close advisers.

The memo says McGahn’s immunity from congressional testimony is separate and broader than a claim of executive privilege.

Former federal prosecutor Mimi Rocah tells me, “This is a political move, not a real legal one and I don’t believe it would be upheld by a court.” She explains, “None of the rationales cited for this immunity, which is far broader than Executive Privilege, apply here. But they needed to give McGahn cover to say no.”

The White House argument is especially weak given that in a case involving Joshua Bolten and Harriet Miers, a federal court in the District of Columbia previously rejected the assertion of an absolute privilege for presidential advisers. Moreover, another D.C. court has held that executive privilege can be waived when the administration “already publicly revealed the sum and substance of the very material it is now seeking to withhold.”

Constitutional scholar Laurence Tribe tells me, "[The White House’s] efforts are totally groundless, as the Harriet Miers case made clear. There simply is no textual, structural, or historical basis for a sitting president to gag his former White House Counsel in response to a House subpoena seeking testimony about possible criminal and potentially impeachable conduct by that president. " He adds, “The place of Congress as a coequal branch would be obliterated if the efforts to silence McGahn could succeed. And all power to hold the president accountable would be destroyed unless those efforts were swiftly repudiated.”

McGahn is not obligated to respect an entirely fraudulent assertion of immunity. His obligation is to respond to a legally authorized subpoena or face the consequences, including contempt. Beyond his legal peril, any pretensions he had to rescue his reputation, following in the footsteps of John Dean, evaporated with his decision to knuckle under to the White House. As Rocah puts it, “He can still testify and he absolutely should both because it’s the right thing to do and because Trump has impugned his integrity and accused him of lying to Mueller.”

Likewise, former Justice Department spokesman Matthew Miller observes, “McGahn should do his patriotic duty and show up.” However, he noted that McGahn has been all too willing to leak stories that make himself sound heroic, but “when it comes time to put his country first, he’s falling into line just like the rest of the acolytes around the president.”

Meanwhile, a federal court in a 41-page opinion rejected Trump’s attempt to block a subpoena for his financial documents from the Mazars accounting firm, emphatically rejecting the notion that Congress lacks oversight authority:

So long as Congress investigates on a subject matter on which “legislation could be had,” Congress acts as contemplated by Article I of the Constitution. Applying those principles here compels the conclusion that President Trump cannot block the subpoena to Mazars. According to the Oversight Committee, it believes that the requested records will aid its consideration of strengthening ethics and disclosure laws, as well as amending the penalties for violating such laws. The Committee also says that the records will assist in monitoring the President’s compliance with the Foreign Emoluments Clauses. These are facially valid legislative purposes, and it is not for the court to question whether the Committee’s actions are truly motivated by political considerations

The court observed, “Congress reasonably might consider those documents in connection with deciding whether to legislate on federal ethics laws and regulations. ... Investigating whether the President is abiding by the Foreign Emoluments Clause is likewise a subject on which legislation, or similar congressional action, could be had.” And Congress, of course, has the impeachment power. “It is simply not fathomable that a Constitution that grants Congress the power to remove a President for reasons including criminal behavior would deny Congress the power to investigate him for unlawful conduct—past or present—even without formally opening an impeachment inquiry,” the court found.

In rejecting Trump’s blanket denial of Congress’s oversight power, the court handed the House its first significant victory in Trump’s ongoing war against the legislative branch. If Trump attempts to block production of documents, he would then be in contempt of court, a new assault on constitutional government.

The ruling should hearten the House on two grounds. First, when dealing with subpoenas and witnesses, the House can turn to the courts to end Trump’s stonewalling. Second, the speed with which the court acted should throw doubt on Trump’s attempts to delay and run out the clock before the 2020 election.

For House Speaker Nancy Pelosi (D-Calif.), under increasing pressure to initiate impeachment hearings, the rule might give her some breathing space. Now, however, it will be up to the House to enlist the judicial branch in compelling witnesses such as McGahn to testify.

We see a crack opening in Trump’s unconstitutional stonewall strategy. It’s the courts that might have the will and the ability to defuse a constitutional standoff.

Read more:

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Henry Olsen: Don’t go wobbly on E-Verify, Mr. President

Brian Klaas: Why no one should be surprised by the latest Trump corruption mess

Greg Sargent: A top Democrat warns: If we don’t confront Trump, he’ll grow more lawless

Catherine Rampell: We don’t know what Trump’s tax returns are hiding. But the hints are troubling.