The big question is what happens next. Do Democrats keep fighting separate battles, or do they go big and initiate impeachment proceedings? House Speaker Nancy Pelosi (D-Calif.) ― who on Thursday accused Barr of committing a crime by lying to Congress ― dismissed the idea of jumping to impeachment on Thursday, sarcastically saying it’s “too good” for the president.

It is normal for an administration to resist congressional oversight but not to do it wholesale. The Trump administration is simultaneously refusing requests for the full Mueller report, the president’s tax returns and several subpoenas for testimony from various officials.

“If one branch of government no longer believes that another branch of government is coequal, and has the authority and the jurisdiction to oversee and investigate, than you are essentially moving toward a dictatorship,” said Rep. Pramila Jayapal (D-Wash.).

Several other Democrats likened Trump to a king or dictator on Thursday ― partly because Barr and other officials have refused to comply with demands for information but also because Trump himself issued a blanket refusal, saying last week that his administration would fight “all the subpoenas.”

“We cannot, we simply cannot, have a presidency that is run as if it were a king or dictator,” House Oversight Committee chair Elijah Cummings (D-Md.) told reporters. “This is a time where in 200 years or beyond people are going to look back at this moment and ask, ’What did you do?”

Democrats were furious Thursday that Attorney General William Barr refused to testify before the House Judiciary Committee or hand over an unredacted version of the Mueller report.

WASHINGTON ― The executive and legislative branches of the federal government are locked into a constitutional showdown in the wake of Robert Mueller ’s special counsel investigation into Russian interference in the 2016 election.

J. Scott Applewhite/Associated Press Speaker of the House Nancy Pelosi (D-Calif.) says impeachment is "too good" for the president at a news conference Thursday on Capitol Hill in Washington.

Democrats can try to enforce their subpoenas in court, where they will have a strong hand but limited time. The Supreme Court has repeatedly held that Congress has broad authority to conduct investigations.

“In general, a congressional subpoena is a powerful instrument, and so eventually I’m sure the attorney general will testify in the House Judiciary Committee,” said Ron Weich, a former Justice Department congressional liaison who is now dean of the University of Baltimore’s law school.

“The competing interests generally favor Congress,” Weich said. “The executive branch’s interest in protecting particular investigative documents works most of the time, but if Congress insists and there’s a subpoena, the constitutional responsibility that Congress has to conduct oversight will ultimately trump those specific objections from the department.”

In his letter refusing to hand over the unredacted Mueller report, the Justice Department’s Stephen Boyd wrote that the committee “has no legitimate role in demanding law enforcement materials with the aim of simply duplicating a criminal inquiry.”

The letter cited past Justice Department legal memos insisting on the need to keep prosecutorial information hidden ― including a 2012 memo by former Attorney General Eric Holder arguing against handing over a more limited category of documents related to Operation Fast and Furious, a botched investigation aimed at gun trafficking.

The situations were quite different. The Obama administration wanted to keep deliberative materials about how to respond to Congress away from congressional investigators, while the Trump administration, at the moment, is refusing to turn over any underlying investigative material at all.

But even the Obama administration’s arguments about confidentiality for Fast and Furious deliberations failed to sway federal judges, who mostly ruled in favor of congressional Republicans.

“As the Fast and Furious litigation shows, if the executive doesn’t reasonably accommodate Congress’ requests for information, it’s going to lose in court,” said Neil Kinkopf, a law professor at Georgia State University College of Law.

The Fast and Furious case also shows the shortcomings of Congress going to court, however. The Obama administration managed to drag out the case with appeals until it was out of power and a new batch of lawmakers had been sworn in. The George W. Bush administration similarly prolonged a court battle with congressional Democrats over their investigation into the improper firings of U.S. attorneys.

At this point, Democrats have only asked for documents and issued subpoenas. They haven’t held any contempt votes or authorized any lawsuits. So any potential legal victories are still a long way off. But that seems where things are headed.

“Everything is so tense now, it seems like everything is going to court,” said Weich.

In the meantime, Democrats are still negotiating with the administration over their various requests. The House Ways and Means Committee is waiting to hear back from the Trump administration on its request for the president’s tax returns, even though the administration has already blown two deadlines.

And the House Oversight Committee was ready to hold former White House personnel official Carl Kline in contempt if he resisted a request for a closed-door interview, but over the weekend it decided to question Kline on Tuesday with a White House lawyer present, which had previously been unacceptable. Cummings said he was unhappy that the White House attorney stopped Kline from answering certain questions about questionable security clearances he’d issued to Trump’s son-in-law, Jared Kushner, and more than two dozen other staffers.

Barr refused to testify this week because he didn’t like the hearing format Democrats had devised, with staff attorneys getting a solid half hour to ask questions instead of the usual five minutes afforded to lawmakers. Former Justice Department official Edgar Chen wrote that an alternative approach would have been to have members allocate their time to one designated member of the committee who could question a witness for an extended period of time.