(William Glasheen/The Post-Crescent via AP)
Opinion writer

Now that Attorney General William P. Barr is apparently threatening not to testify to Congress about the Mueller report’s findings, the difficulties Democrats face in holding President Trump accountable for his corruption and lawlessness are growing more acute by the day.

Democrats are vowing to subpoena Barr if he does not come voluntarily. But this move might not necessarily solve the broader problem: If the Trump administration carries out his promise of maximal resistance to oversight on every front, that could bog down Democratic efforts in court battles that stretch on and on with little to show for them.

So here’s one possible response: Democrats could more explicitly threaten an impeachment inquiry if Trump’s threat of total resistance is realized. Democrats have suggested such an inquiry might happen at some unspecified point, depending on what emerges during the current hearings they’re trying to conduct.

But a more aggressive approach would tie the threat of impeachment directly to Trump’s current stonewalling.

In an interview, Rep. Ted Lieu (D-Calif.), a member of the House Democratic policy leadership team who sits on the Judiciary Committee, told me that House Democrats must be prepared to take this step.

“If we can’t fact-gather, we’re going to have to use the other tools at our disposal and make sure our oversight responsibilities are respected,” Lieu said.

Barr’s stonewalling

With his threat not to appear before the Judiciary Committee, Barr is trying to dictate the terms, in a very heavy-handed fashion, under which he is questioned by Congress. As The Post reports, Barr is objecting because Democrats want to subject him to lengthy questioning, carried out by committee lawyers.

Barr is also balking at another demand: Democrats want to retain the option of questioning Barr in a closed-door session about material in special counsel Robert S. Mueller III’s report that remains redacted. Barr says this would interfere with his ability to deliver his testimony as he had hoped to.

All this comes as Barr has still not said whether he’ll give Congress the unredacted Mueller report and its underlying investigative materials.

Meanwhile, the White House is preparing to try to claim executive privilege to block former White House counsel Donald McGahn from testifying, as Democrats have subpoenaed him to do. McGahn could shed light on some of Trump’s worst obstruction-of-justice episodes, including Trump’s effort to get him to remove Mueller, which Trump then pressed McGahn to lie about.

On top of all that, the Treasury Department is still rejecting Democratic demands for Trump’s tax returns. Legal experts have said that if Democrats do launch an impeachment inquiry, it could strengthen Democrats’ legal hand in compelling cooperation on multiple fronts.

The impeachment threat

In our interview, Lieu said he agrees with this analysis, and that this is why Democrats should be prepared to launch an impeachment inquiry in direct response to maximal stonewalling.

Lieu conceded that right at this moment, there may not be sufficient support in the Democratic caucus for initiating such an inquiry. But, importantly, Lieu noted that total resistance to oversight could push the caucus toward favoring one.

“I don’t think the caucus is there in terms of launching an impeachment inquiry into obstruction of justice,” Lieu told me. But he added: “If it turns out we can’t investigate, because the White House is not complying with anything that Congress requests, then I think the caucus would support an article of impeachment on obstructing Congress in order to maximize our court position.”

Lieu noted that one way to do this could be for the Judiciary Committee to advance one article of impeachment (for corruptly defying congressional subpoenas and oversight) as the subject of hearings, pointing out that the third article of impeachment against President Richard Nixon was precisely this.

Lieu also told me that the House should vote to hold Barr in contempt very quickly if he does not turn over the full Mueller report, and Lieu expects the same treatment for McGahn, if he goes along with Trump’s efforts to block his testimony.

What’s really at stake here

Basically, the question we face is whether Trump will be permitted to neuter the House’s oversight authority, thus placing himself beyond accountability and doing serious damage to our constitutional order.

Mark Rozell, a professor of government at George Mason University, has written extensively about the core principles at stake in such battles. He has concluded that, while the executive branch does have legitimate constitutional grounds for maintaining secrecy in some cases as a necessary component of governing, this power is not absolute and can be flagrantly abused, particularly if it’s designed to impede Congress’s legitimate constitutional oversight role, as happened under Nixon.

Rozell also notes that the impeachment threat is a legitimate response to such extreme resistance to oversight. He emailed me: “Congress has many tools at its disposal to pressure the White House to release information or permit testimony, and potentially the most powerful among them is the threat of impeachment hearings.”

The case for launching an impeachment inquiry is already strong. As Benjamin Wittes writes, the Mueller report details a whole range of Trump’s abuses of power, from multiple bids to shut down or impede the investigation to efforts to turn law enforcement loose on his political foes, that all rise to “the sort of conduct the impeachment clauses were written to address.”

Democrats are not at this point yet. But if that is to be, their own posture suggests another way forward. They themselves have said that fact-gathering and accountability can proceed for now outside an impeachment inquiry. But if Trump won’t allow that, they can threaten an impeachment inquiry in response, and note quite correctly that Trump is forcing them into it.

After all, what’s the alternative?

Read more:

Greg Sargent: How Trump may be making his own impeachment more likely

Jennifer Rubin: President Trump, constitutional menace

Paul Waldman: Trump’s strategy to declare himself above the law and escape accountability

Harry Litman: Can Trump resist a subpoena?

Irvin B. Nathan: Be warned, Congress. Subpoenas may not uncover the Trump administration’s secrets.