If Democrats on the House Judiciary Committee authorize congressional subpoenas Wednesday for the full special counsel report and underlying evidence, it won’t immediately start a legal showdown between the legislative and executive branches.

But the resolution would give Chairman Jerrold Nadler the discretion to throw the first punch, even as the terms of that looming separation of powers fight remain unsettled.

The New York Democrat and other House committee leaders gave Attorney General William Barr a deadline of Tuesday to send Congress the full report from special counsel Robert S. Mueller III, without redactions. That looks unlikely to happen. Barr responded last week in a letter that he intends to release a redacted version of the report “by mid-April, if not sooner.”

House Democrats don’t have a mechanism to quickly enforce executive branch compliance with a congressional subpoena — and certainly not by the time Barr makes his release in mid-April. Wednesday’s scheduled markup on the resolution, for now, appears to only give lawmakers some leverage in any discussions with the Justice Department as they wait to see what will be included.

Nadler, in announcing the markup on subpoenas, encouraged Barr to reconsider what he planned to redact from the report “so that we can work together to ensure the maximum transparency of this important report to both Congress and the American people.”

Watch: The back and forth on why Mueller’s report hasn’t been released yet

And in a three-page letter to Barr late Monday, with a nine-page appendix that includes legal arguments about why information should not be withheld, Nadler and other Democratic committee chairpersons wrote that they hope to avoid resorting to a “compulsory process.”

Democrats are unlikely to be satisfied. The attorney general indicated in his letter that he would withhold certain information, including material related to grand juries and “information that would unduly infringe on the personal privacy and reputational interests of peripheral third parties.”

The question remains how unsatisfied Democrats will be and what they would do to enforce any subpoena or exert pressure on the Justice Department.

“If the department is unwilling to produce the full report voluntarily, then we will do everything in our power to secure it for ourselves,” Nadler wrote Monday in an op-ed in The New York Times. “We require the full report — the special counsel’s words, not the attorney general’s summary or a redacted version.”

Congress currently relies on two formal mechanisms to enforce subpoenas, and recent controversies suggest that they are not certain to get lawmakers the information they seek.

One path is criminal contempt of Congress, which has been used four times since 2008 and most notably with then-Attorney General Eric H. Holder Jr. during the congressional probe into the government’s botched Fast and Furious gun smuggling operation, a Congressional Research Service report from March states.

While an 1857 law makes it a misdemeanor to “willfully” fail to comply with a subpoena and appears to impose mandatory duty on a U.S. attorney to submit a violation to a grand jury, the executive branch makes that decision with discretion and is unlikely to charge, and so is not a credible threat, CRS states.

The second and potentially more fruitful path is civil enforcement, where the House could authorize a lawsuit for a court order declaring that Barr must comply with the subpoena, a tactic Republican lawmakers also used in the Fast and Furious probe in 2012.

But that process can be slow. The Fast and Furious lawsuit still hasn’t been finally settled more than six years later, a timeframe that diminishes both the value of the disclosure of the information and the committee’s ability to engage in timely oversight, the CRS report states.

It’s also too early to tell how any courtroom battle would play out, because it’s unclear what information would be fought over and on what terms.

For example, one of the potential big legal quarrels could be about any information the White House withholds on claims of executive privilege. But Barr told lawmakers last week that there are no plans for redactions based on that.

“Although the president would have the right to assert privilege over certain parts of the report, he has stated publicly that he intends to defer to me, and, accordingly, there are no plans to submit the report to the White House for a privilege review,” Barr wrote.

Another fight could be over grand jury information. Barr wrote that the information “by law cannot be made public,” and the top Republican on the committee, Rep. Doug Collins of Georgia, cited that as part of his reason for opposing a subpoena.

“Judiciary Democrats have escalated from setting arbitrary deadlines to demanding unredacted material that Congress does not, in truth, require and that the law does not allow to be shared outside the Justice Department,” Collins said.

But Democrats dispute that it can’t be given to Congress, and there are other interests and groups at play in a legal fight that could reveal some of that information. The Reporters Committee for the Freedom of the Press filed an application Monday in federal court to authorize the release of grand jury material in the Mueller report, part of its effort to obtain the report under public record laws.

The group asks that Barr be ordered to give the court a copy of the special counsel report to review it as part of their request. And it notes that Washington courts previously ordered disclosure of President Richard Nixon’s grand jury testimony, dockets related to the independent counsel investigation into President Bill Clinton and the release of an independent counsel report on Iran-Contra matters.

“This was no ordinary secret grand jury investigation but rather one that was in many respects public and that has affected the entire country and all branches of the federal government,” the group wrote in the court filing. “The interests of history and the public ‘overwhelm’ any need to maintain secrecy of such grand jury material.”

That there is no exact precedent to a fight over the Mueller report adds uncertainty to the legal fight as well. Any courtroom conflict on something like executive privilege would ultimately be a balancing test for judges, CRS states.

“Yet judicial decisions and historical practice have set few clear legal standards for application in such disputes — except to establish that neither side’s power is absolute and that Congress and the President have an obligation to attempt to accommodate each other’s needs,” the CRS report states.

In the meantime, CRS notes, Congress can encourage disclosure by wielding its powers: negotiation, accommodation and compromise, or constitutional powers such as withholding appropriations, impeachment or its control over agency authority.

“Or, instead of subpoena, if Barr won’t turn over Mueller Report to Congress, House should defund the Office of the Attorney General and Barr’s salary,” Neal Katyal, an appellate lawyer who helped write the Justice Department’s special counsel regulations, tweeted on Friday.