A standoff between Justice Department officials and GOP lawmakers escalated Wednesday as President Trump waded into a controversy over demands to release a highly sensitive document outlining who and what is being investigated by special counsel Robert S. Mueller III.

The Justice Department has refused to turn over the document, known as a “scope memo,” citing its own independence and longtime precedent that it doesn’t disclose the details of ongoing investigations.

“A Rigged System — They don’t want to turn over Documents to Congress. What are they afraid of? Why so much redacting? Why such unequal “justice?” At some point I will have no choice but to use the powers granted to the Presidency and get involved!” the president tweeted Wednesday morning.

At the same time, a bloc of Trump-allied House Republicans has been discussing a parliamentary maneuver to initiate impeachment proceedings against Deputy Attorney General Rod J. Rosenstein, who wrote the scope memo and oversees the Mueller investigation into Russian interference in the 2016 election and related matters.

Such a move in the House, which returns Monday, might have little hope of ultimate success, but a floor debate on Rosenstein could fuel the conservative push to curtail or end the Russia investigation.

The conflict has been brewing for weeks, but positions hardened in recent days, after Justice Department officials told lawmakers Monday that they would not be divulging the contents of the memo to Reps. Mark Meadows (R-N.C.) and Jim Jordan (R-Ohio), according to officials familiar with the matter.

Then Rosenstein declared Tuesday at a public event that “the Justice Department is not going to be extorted” by public and private threats.

Precisely how the president might get involved is unclear, but officials familiar with behind-the-scenes discussions said pressure has been building over Meadows’s demand that he and others be allowed to review the scope memo from Rosenstein spelling out which areas of investigation he has authorized Mueller to pursue.

Meadows and Trump talk frequently and often discuss their shared frustrations with Justice Department officials, according to officials familiar with the matter.

A heavily redacted version of the scope memo has emerged in the pretrial hearings of former Trump campaign chairman Paul Manafort, but Meadows and Jordan, two of the president’s fiercest defenders, want to see the rest of it.

Within the Justice Department, which has provided other sensitive documents to lawmakers in recent weeks, the demand to see the scope memo is viewed as a request that cannot be fulfilled, according to people familiar with the discussions, because that memo would reveal highly sensitive details of an ongoing investigation — information that could compromise Mueller’s work. Some department lawyers have also argued that sharing that memo would be an unprecedented violation of the Justice Department’s independence, according to people familiar with the discussions who, like others, spoke on the condition of anonymity to discuss internal deliberations.

These people argued that it has always been a hard-fought principle of both Republican and Democratic administrations not to provide details of an ongoing investigation to Congress. And in this case, the investigation involves a probe of the president and his associates, making it that much more important not to share the material with elected officials, these people said.

“There is a certain amount of give-and-take here, but providing [surveillance] applications and internal memoranda in open law enforcement investigations is well outside historical norms,” said David Kris, a former senior Justice Department official who now has his own consulting firm, Culper Partners. “But it is also well outside historical norms for the president himself, who leads the executive branch and controls the invocation of executive privilege, to be tweeting attacks on the Department of Justice for adhering to traditional limits.”

The Justice Department has already turned over other documents relating to the FBI’s work, including memos that former director James B. Comey wrote about his private meetings with Trump, as well as an internal FBI document from 2016 that initiated a key stage of the investigation into whether any Trump associates coordinated with the Kremlin in trying to influence the presidential election.

Justice Department officials said dozens of lawmakers and staff members from both parties have also viewed thousands of classified pages, in a process that now includes members of both parties being given temporary office space at the Justice Department to review the documents.

Many of the documents being sought are already the subject of a long-running inspector general investigation. That inquiry is expected to culminate in a public report in a matter of weeks.

For months, Trump has complained privately and publicly about Rosenstein, leaving many inside the department worrying that the deputy attorney general, who oversees the Mueller investigation, could eventually be fired.

Senate Minority Leader Charles E. Schumer (D-N.Y.) on Wednesday warned Trump against doing so, tweeting: “Mr. President, the powers of the Presidency do not give you the right to interfere with or shut down the Russia investigation. Firing the Deputy AG or Director Mueller would create a constitutional crisis. Do not go down this road.”

At an appearance Tuesday at the Newseum in Washington, Rosenstein said the department would resist efforts to force officials to reveal sensitive material on an ongoing investigation.

“I think they should understand by now that the Department of Justice is not going to be extorted,” Rosenstein said. “We’re going to do what’s required by the rule of law, and any kind of threats that anybody makes are not going to affect the way we do our job.”

Meadows and Jordan, as two members of the conservative House Freedom Caucus, have been in a months-long fight with the department over what they say is its failure to turn over relevant documents, including those related to the court-approved surveillance of former Trump campaign adviser Carter Page.

That effort poses another potential threat to Rosenstein — and a possible Republican crisis on Capitol Hill — in the form of a legislative tactic known as a “privileged” resolution. Meadows and several other House conservatives are considering offering articles of impeachment against Rosenstein within that framework at some point — in effect using House rules that allow for an immediate, “privileged” floor vote as the means of shepherding their measure before the chamber, according to three people familiar with the discussions who were not authorized to speak publicly.

Should conservatives decide to push for a vote on impeaching Rosenstein, it would put House Speaker Paul D. Ryan (R-Wis.) in the difficult position of having to decide whether to allow such a vote or to table the bill or recommend it to the House Judiciary Committee — a rebuff that could anger Republicans on and off Capitol Hill who want to see action against the Justice Department.

And if a vote was allowed
under “privileged” circumstances, House Republicans would then have to publicly declare whether Rosenstein should stay or go — a vote many lawmakers are wary of having to make before this year’s midterm elections.

In an interview this week, Meadows did not rule out pursuing that option. “My frustrations about their inability to respond to simple requests could warrant further action,” Meadows said, adding that many of his colleagues are nearing a breaking point with Rosenstein.

Still, impeaching a federal official is an exceedingly difficult endeavor. While House members can refer impeachment articles to the House Judiciary Committee, it is usually up to the committee to debate or draft impeachment legislation that could be brought before the House for a vote. A simple majority is then needed for an article of impeachment to pass and be sent to the U.S. Senate for a trial. Two-thirds of the Senate is necessary to convict and remove the accused from office.

The last federal official impeached by the House was U.S. District Judge G. Thomas Porteous Jr., who was convicted by the Senate in 2010 on bribery allegations.

Ellen Nakashima contributed to this report.