WASHINGTON (Reuters) - Some U.S. House Democrats on Thursday said they might seek to invoke a dormant congressional power to impose fines on Attorney General William Barr after he refused to provide them with an unredacted copy of the Mueller report.

U.S. Attorney General William Barr smiles as he returns to testify on "the Justice Department's investigation of Russian interference with the 2016 presidential election" after a break in the hearing on Capitol Hill in Washington, U.S., May 1, 2019. REUTERS/Clodagh Kilcoyne

Discussion of using their “inherent contempt” power came after Barr also refused to appear at a House of Representatives Judiciary Committee hearing meant to delve into his handling of the report by Special Counsel Robert Mueller.

“Congress’ power will not be abdicated. We will enforce it,” Democrat Ted Lieu told reporters in remarks that reflected a growing view among some Democrats that President Donald Trump is challenging the basic oversight role of Congress.

“We can start imposing fines on that person immediately upon contempt off the House floor. And we will go there if he does not cooperate,” said Lieu, a House Judiciary Committee member.

House Judiciary Committee Chairman Jerrold Nadler said he may move to hold Barr in contempt of Congress over his refusal to comply with the subpoena for the full report, which describes Russia’s interference in Trump’s favor in the 2016 U.S. election and Trump’s subsequent attempts to impede Mueller’s probe.

The Trump administration’s efforts to stonewall several congressional probes of the president, his family and his businesses are pushing congressional Democrats to explore options to enforce subpoenas.

The unprecedented imposition of fines would represent an aggressive counter attack to the Trump administration.

A Justice Department spokeswoman had no comment.

A contempt citation is a legal tool to put some bite into their investigations, though it is not often used.

A contempt finding requires majority votes by the committee involved and then the full House or Senate, but not both.

Enforcement would normally be done through the courts. But some lawmakers said the “inherent contempt” power allows them to instruct the sergeant-at-arms of the House to jail a defiant witness or impose fines outside the federal court system.

“We will explore all the options, and inherent contempt is certainly one of the options,” Nadler said.

It is unclear to what extent Congress could try to enforce a contempt citation on its own.

“I don’t think Congress has ever imposed fines as part of the contempt proceeding,” said Michael Stern, a former U.S. House senior counsel.

“There is a general sense that fines could be used, but they never have been. There is no rule that provides for it.”

Prior case law underpins Congress’ inherent contempt authority to jail people.

While those cases did not explicitly deal with fines, some legal experts have interpreted the rulings to extend that power to Congress so they are on par with federal judges.

A Supreme Court case in 1821 found that the “constitutional right of self-preservation” for both courts and Congress were “analogous,” said Morton Rosenberg, a retired Congressional Research Service legal analyst.

He added that if Congress wants to impose fines on Barr, it would need to pass a resolution outlining a framework for doing so.