WASHINGTON — When President Trump declared that the special counsel, Robert S. Mueller III, “should not testify” before Congress, he contradicted Attorney General William P. Barr, who had already told lawmakers that he had no objection to letting Mr. Mueller talk to them.
That clash has raised the prospect of a major test of Justice Department independence on Mr. Barr’s watch.
Defying Mr. Trump would be awkward for Mr. Barr in part because he has long subscribed to a sweeping theory of executive power under which Mr. Trump may rightfully override and control any discretionary decision by a subordinate executive branch official. In Mr. Barr’s words, the president, not the attorney general, is the nation’s “top law enforcement officer.”
And while the Trump team has been pleased with Mr. Barr’s handling of the Mueller investigation, disregarding Mr. Trump’s desires risks angering a mercurial president who turned on other once-favored subordinates — including excoriating Mr. Barr’s predecessor, former Attorney General Jeff Sessions, for his refusal to retain oversight of the Russia investigation.
But Mr. Barr, citing his age and lack of further aspirations, promised Congress during his confirmation hearing in January that “I will not be bullied into doing anything I think is wrong by anybody, whether it be editorial boards or Congress or the president. I’m going to do what I think is right.”
For now, Mr. Barr has given no public sign that he will revoke his permission for Mr. Mueller to testify in response to the president’s statement. Mr. Barr appears to be adopting a tentative strategy of trying to tiptoe past Mr. Trump’s challenge by interpreting the pronouncement as a mere expression of opinion by the president rather than as an order.
A spokeswoman for Mr. Barr declined to say whether the attorney general had changed his position, but a person close to Mr. Barr emphasized that he had testified several times under oath that he had no objections to the special counsel testifying.
Mr. Barr appears to be trying to find a way to protect his professional integrity and not look like a “lackey” to Mr. Trump, but “without alienating his boss,” said Bruce Buchanan, an emeritus professor of government at the University of Texas at Austin.
“Barr is trying to avoid getting himself into a position of defying the president even though he doesn’t want to keep Mueller from testifying,” Mr. Buchanan added. “He would prefer not to do it frontally and baldly, and yet still find a way to squirm out of the situation.”
But that solution to Mr. Barr’s dilemma is fragile.
It would collapse if Mr. Trump, who tweeted his objection to Mr. Mueller’s potential testimony over the weekend, were to decide to press the issue by explicitly ordering Mr. Barr to gag the special counsel. Mr. Barr’s handling of the Mueller report so far has prompted critics to accuse him of acting more like the president’s lawyer than an honest broker.
But if Mr. Barr ignores Mr. Trump’s statement because it fell short of a formal and direct order, that would be the behavior of an attorney general who sees his client more as the presidency as an institution than Mr. Trump, said Harold Bruff, a University of Colorado emeritus law professor and co-author of a separation-of-powers casebook.
“Who is his client?” Mr. Bruff said. “Is his client the person who is the president? If so, then the merest suggestion is as close to an order as you need. It’s a little like being married.”
Whether Mr. Mueller testifies is a decision that Mr. Barr — and perhaps Mr. Trump — can control because the special counsel remains a Justice Department employee. It is not clear when Mr. Mueller will return to life as a private citizen; a spokesman has said for weeks that Mr. Mueller would be leaving “in coming days.”
If Mr. Trump does decide to insist that Mr. Barr gag Mr. Mueller, the attorney general could seek to resolve his dilemma by slow-walking any official change in position until Mr. Mueller is no longer his subordinate.
But House Democrats see it as urgent to obtain Mr. Mueller’s public testimony as soon as possible, perhaps as early as next week.
The growing tensions comes against the backdrop of many other fights over House demands for information that Mr. Trump is stonewalling.
On Tuesday, the White House told the Judiciary Committee that it had instructed Mr. Trump’s former White House counsel, Donald F. McGahn II, not to comply with a subpoena for copies of administration documents in his possession, and to instead direct all requests for them to the White House.
Meanwhile, the Judiciary Committee is set to vote on Wednesday whether to recommend that the House hold Mr. Barr in contempt of Congress for not turning over an unredacted version of Mr. Mueller’s report.
The Democratic-led House Judiciary Committee has invited Mr. Mueller to testify broadly about the special counsel investigation’s findings and conclusions. Among other things, Democrats want to press Mr. Mueller to explain why he held off from deciding whether to accuse Mr. Trump of obstruction, and what he thinks of Mr. Barr’s pronouncement that the evidence does not establish that Mr. Trump committed such crimes.
Senator Lindsey Graham, the South Carolina Republican who is chairman of the Senate Judiciary Committee, has invited Mr. Mueller to testify before that panel for a narrower purpose: whether he objects to Mr. Barr’s account, in testimony last week, of a phone call between the two of them in late March. At the time, Mr. Mueller had complained that Mr. Barr’s initial framing of his then-still-secret report’s conclusions in a four-page letter was flawed and had unsuccessfully urged the attorney general to immediately release the document’s two executive summaries.
Testifying last week before the Senate panel, Mr. Barr claimed that Mr. Mueller had assured him that nothing in his letter was inaccurate, and that the special counsel had said in a phone call that his concerns were instead that news media coverage of the letter was causing public confusion.
After Mr. Mueller leaves the Justice Department, Mr. Trump will have significantly less control over him. But the president could still attempt to invoke executive privilege to keep Mr. Mueller from testifying and, in theory, take the unusual step of filing a lawsuit seeking a court injunction gagging him.
Such litigation would face steep obstacles to success: Mr. Barr already made most of Mr. Mueller’s report public, an action that a court could find waived executive privilege over those materials. But the fight could take a long time to play out.