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Opinion writer

President Trump has now formally exerted executive privilege over the redacted portions of the Mueller report and its underlying materials — defying a House subpoena for those materials, and confirming once again that Trump will exercise maximal resistance to any and all oversight and accountability.

This march into treating the House as fundamentally illegitimate is going to make it harder and harder for Democrats to resist launching an impeachment inquiry.

In an interview, Rep. Adam B. Schiff (D-Calif) — the chair of the House Intelligence Committee — said that if things continue on their current course, it will escalate the chances that “we end up in a constitutional confrontation” and will add to “the weight behind an impeachment process.”

“Obstruction of Congress was one of the bases on which the impeachment of Richard Nixon was sought,” Schiff told me. “Obstruction of Congress, following on the obstruction of the Mueller investigation, does strengthen the case to move forward with an impeachment proceeding.”

Schiff has previously advised squarely against impeachment, saying that if Republican lawmakers cannot make the case to their voters — that is, to Republican voters — that Trump’s conduct merits impeachment, it will be “seen by a substantial part of the country as merely an effort to nullify an election by other means.”

But now, Schiff is talking about an impeachment inquiry as something that Democrats may be forced to resort to, in response to continued across-the-board stonewalling from Trump, regardless of what Republicans think.

And while Schiff has previously said he might support an impeachment inquiry at some point, he’s now saying the case for it is getting stronger.

In exerting executive privilege to keep the full Mueller report concealed, Trump, with the active assistance of Attorney General William P. Barr, bucked a Judiciary Committee subpoena for the redacted and underlying materials.

As former prosecutor Mimi Rocah put it, this has the makings of a constitutional crisis, because “the head of the Justice Department” is helping to block congressional investigations into the president “regardless of law or merit.”

On top of that, Trump is laying the groundwork to try to prevent former White House counsel Donald McGahn, who witnessed multiple Trump efforts to obstruct justice, and possibly even special counsel Robert S. Mueller III from testifying to Congress. The administration is refusing to release Trump’s tax returns, violating the law. And Trump has vowed to fight “all” subpoenas.

Schiff is also getting stonewalled in another way. The House Intelligence Committee is asking the FBI to supply the findings of its counterintelligence investigation — which is separate from those of its criminal investigation, and thus were not included in the Mueller report. As Martin Lederman explains, the FBI is legally required to keep intelligence committees informed of such matters.

But a committee aide told the New York Times that this information has not been forthcoming, and that the committee may resort to a subpoena.

These counterintelligence findings are a big missing piece of the puzzle. As Ryan Goodman noted, we still don’t know what the special counsel and/or the FBI have determined “with respect to whether Trump associates engaged in reciprocal efforts with Russian agents without entering a criminal agreement to do so, whether Americans have been witting or unwitting Russian assets, and what leverage or influence Moscow may have over particular individuals.”

Schiff confirmed to me that this information is being withheld, and noted that on this matter, there may be a divide among intelligence professionals on one side, and Barr and the White House on the other.

“I think the FBI is willing to be more forthcoming,” Schiff said. “I think the FBI and intelligence community are mindful of their statutory obligations, and they’re caught between a rock and a hard place with the combative posture that Bill Barr has taken.”

“I think this is being driven by the White House, and I think Bill Barr is acting as the president’s lieutenant,” Schiff added.

As I’ve reported, some legal experts believe impeachment hearings could strengthen the legal hand of Democrats in forcing compliance with their oversight demands. A House Watergate lawyer amplified that case to the Times.

In our conversation, Schiff didn’t take a position in that debate. But he did say that “these continued acts of willful obstruction add new weight to those who have advocated impeachment.”

“That will be particularly so if the court finds that we can only gain access to some of these records if that formal process is initiated,” Schiff said. “The case for compliance is compelling, preliminary to a potential impeachment proceeding. If a court were to find otherwise, that would certainly strengthen the case for impeachment.”

“We are determined to make sure that the stonewalling of our oversight responsibility is unsuccessful,” Schiff said.

At the end of the day, House Democrats may have to choose between allowing that stonewalling to be successful, or pulling the trigger on an impeachment inquiry — that is, to choose between total capitulation and total confrontation.

Read more:

Jennifer Rubin: ‘Self-impeachable’ is exactly right

The Post’s View: The Trump administration is in contempt of Congress

Greg Sargent: The nightmare scenario for Democrats on Trump’s corruption

David E. Kendall: Mueller’s conclusion was a dereliction of his duty

Henry Olsen: Trump should resist giving up his tax returns with every bone in his body