In many ways, the letter that President-elect Donald J. Trump’s criminal defense lawyers sent to the Justice Department this week was a display of legal and political bombast.

The lawyers, Todd Blanche and Emil Bove, sought in it to prevent the special counsel, Jack Smith, from releasing a report about his inquiry into Mr. Trump’s mishandling of classified material.

They accused Mr. Smith of “unethical” and “improper” behavior for how he has handled the case, using damning phrases like “dereliction of duty” and accusing the special counsel of “leaking sensitive details” to the news media. Mr. Blanche and Mr. Bove have for many months launched similar attacks against Mr. Smith and his team.

But while the tone of denunciation was familiar, the accusations themselves carry new weight now that Mr. Trump, who has often suggested that Mr. Smith is corrupt and should face consequences for bringing charges against him, has won the election.

And the letter’s aggressive posture was all the more fraught and remarkable because Mr. Blanche and Mr. Bove are now poised to assume senior positions in Mr. Trump’s Justice Department, where they could soon have a say in how to evaluate — or even punish — Mr. Smith and his deputies.

There is no precedent for a situation in which a former president’s criminal defense lawyers go almost overnight from representing him against the federal government to being high-ranking officials in an administration led by that same client — one who has regularly signaled that he wants to use the Justice Department to mete out retribution against his perceived opponents.

It is less clear whether seasoned former prosecutors like Mr. Blanche and Mr. Bove would follow instructions to do so, especially when there has been no evidence produced that Mr. Smith has committed an ethical breach, let alone a prosecutable offense.

Nevertheless, the angry accusations that Mr. Smith misused his prosecutorial powers — or relied on powers that he does not have — cannot be ignored: They are coming from two lawyers who are about to help lead the Justice Department and assume such powers themselves.

Mr. Trump’s lawyers contend that the issuance of a final report amounts to unethical conduct by Mr. Smith, and yet it is not clear that the special counsel could avoid doing so even if he wanted to.

Justice Department regulations require special counsels, upon finishing their work, to submit a report to the attorney general. In recent years, it has been the practice of department leaders to publicly release reports, albeit often with redactions to protect grand jury testimony or classified materials.

One person close to the Trump team said the incoming president’s advisers saw the speed with which Mr. Smith was trying to make the report public, before Mr. Trump begins his new term, as a political act of its own. The person noted that the special counsel in the Russia inquiry, Robert S. Mueller III, took nearly two years to issue a report about whether the Trump campaign had conspired with Russians and whether Mr. Trump had obstructed that investigation. The report did not make a recommendation about prosecuting a sitting president, which is against longstanding Justice Department policy.

Mr. Blanche is Mr. Trump’s choice to become the deputy attorney general. That position would give him the authority to make decisions not only about who should face charges, but also about issues of internal department discipline, assignments and termination. Mr. Bove is expected to take the job of principal associate deputy attorney general, a post that would make him Mr. Blanche’s right-hand man.

The closer they get to assuming those roles, the more their legal work on behalf of their powerful client, Mr. Trump, may be seen both inside and outside the department as an indicator of how they intend to run it.

Indeed, their letter to Attorney General Merrick B. Garland could become a blueprint of sorts for how they and other Justice Department officials might go after those who were involved in the investigations and prosecutions of Mr. Trump by reassigning, demoting or even seeking to fire them.

Mr. Blanche and Mr. Bove did not respond to a message seeking comment. Steven Cheung, Mr. Trump’s communications director, did not directly address a question about the letter and its authors, instead saying that Mr. Smith should not be allowed to “prepare an unconstitutional, one-sided, falsehood-ridden screed.” He suggested that the Justice Department should push to keep the report from being released.

A few weeks before the election, Mr. Trump declared that he would fire Mr. Smith in “two seconds” if he was still in place after Inauguration Day, adding the next day that Mr. Smith should be “thrown out of” the country. Mr. Smith and many members of his team plan to resign from the department before Mr. Trump or his deputies have a chance to fire them, according to people familiar with their plans.

The process of the Smith team’s departures has already begun.

Jay Bratt, a counterintelligence prosecutor and a key member of the classified documents team, retired on Friday, after 34 years of service. Mr. Bratt, 65, played a key role in the early days of the investigation and went on to become a critical member of Mr. Smith’s team.

Mr. Trump has long pushed lawyers representing him to be as aggressive as possible, and Mr. Blanche and Mr. Bove have often taken that advice. Twice now, judges overseeing cases they have worked on have reprimanded them for appearing to go beyond the normal boundaries of zealous legal advocacy.

Just this week, Justice Juan M. Merchan, who is scheduled to sentence Mr. Trump on Friday for his 34 felony convictions in Manhattan, chided both men in a written order for “coming dangerously close to crossing the line of zealous representation” and for using “rhetoric that has no place in legal pleadings.”

In October, Tanya S. Chutkan, the federal judge who handled Mr. Trump’s now-defunct election interference case, accused them of repeatedly “focusing on political rhetoric rather than addressing the legal issues at hand.”

“Not only is that focus unresponsive and unhelpful to the court,” Judge Chutkan wrote, “but it is also unbefitting of experienced defense counsel and undermining of the judicial proceedings in this case.”

Mr. Smith has said he intends to file his report on the classified documents case to Mr. Garland and resign from his position before the Trump administration begins.

In a surprise move, however, the judge overseeing the documents case, Aileen M. Cannon, issued a ruling on Tuesday temporarily blocking the release of the report.

Mr. Smith has said in court filings that his report will have two volumes: one for each of the indictments he brought against the president-elect. Judge Cannon’s order barring the release of the report did not appear to distinguish between the documents case, which she oversaw, and the election interference case, which Judge Chutkan heard in Washington.