Jan. 6 Committee Appears to Lay Out Road Map for Prosecuting Trump

He had means, motive and opportunity. But did Donald J. Trump commit a crime?

A House committee explicitly declared that he did by conspiring to overturn an election. The attorney general, however, has not weighed in. And a jury of his peers may never hear the case.

The first prime-time hearing into the Jan. 6, 2021, attack on the Capitol this past week confronted the fundamental question that has haunted Mr. Trump, the 45th president, ever since he left office: Should he be prosecuted in a criminal court for his relentless efforts to defy the will of the voters and hang on to power?

For two hours on Thursday night, the House committee investigating the Capitol attack detailed what it called Mr. Trump’s “illegal” and “unconstitutional” seven-part plan to prevent the transfer of power. The panel invoked the Justice Department, citing charges of seditious conspiracy filed against some of the attackers, and seemed to be laying out a road map for Attorney General Merrick B. Garland to their central target.

In presenting her summary of the evidence, Representative Liz Cheney, Republican of Wyoming and the committee’s vice chairwoman, demonstrated that Mr. Trump was told repeatedly by his own advisers that he had lost the election yet repeatedly lied to the country by claiming it had been stolen. He pressured state and federal officials, members of Congress and even his own vice president to disregard vote tallies in key states. And he encouraged the mob led by extremist groups like the Proud Boys while making no serious effort to stop the attack once it began.

“I think the committee, especially Liz Cheney, outlined a powerful criminal case against the former president,” said Neal K. Katyal, a former acting solicitor general under President Barack Obama.

“A crime requires two things — a bad act and criminal intent,” Mr. Katyal said. By citing testimony by Mr. Trump’s own attorney general, a lawyer for his campaign and others who told him that he had lost and then documenting his failure to act once supporters stormed the Capitol, Mr. Katyal said, the panel addressed both of those requirements.

Mr. Trump’s allies have dismissed the hearings as a partisan effort to damage him before the 2024 election when he may run for president again. And legal defenders argued that the facts presented by the panel did not support the conclusions that it drew.

“Unless there’s more evidence to come that we don’t know about, I don’t see a criminal case against the former president,” said Robert W. Ray, a former independent counsel who investigated President Bill Clinton and later served as a defense lawyer for Mr. Trump at his first Senate impeachment trial.

“Whatever the Proud Boys had in mind when they stormed the Capitol, I don’t see how you’d be able to prove that Trump knew that that was the purpose of the conspiracy,” Mr. Ray added. “Whether or not he ‘lit the fuse’ that caused that to happen, the government would have to prove he knowingly joined that conspiracy with that objective.”

Beyond the legal requirements of making a criminal case, the prospect of prosecuting a former president also would entail far deeper considerations and broader consequences. Criminal charges against Mr. Trump brought by the administration of the man who defeated him would further inflame an already polarized country. It would consume national attention for months or longer and potentially set a precedent for less meritorious cases against future presidents by successors of the opposite party.

“That’s a hill that no federal prosecutor has tried to climb, prosecuting a former president,” said John Q. Barrett, a former associate independent counsel in the Iran-contra investigation. “It’s very fraught,” he said. “It’s a massive undertaking as an investigation, as a trial, as a national saga and trauma.” But he added that accountability was important and that “the threat to the continuity of our government is about as grave as it gets.”

All of which is almost certainly going through the mind of Mr. Garland, a mild-mannered, highly deliberative former federal appeals court judge who has largely kept mum about his thinking. A Justice Department spokesman said Mr. Garland watched the hearing but would not elaborate.

Many officials and rank-and-file prosecutors scattered throughout the 115,000-person Justice Department have long believed that Mr. Trump acted corruptly, particularly in pressuring their own department to parrot his baseless claims of election fraud, according to several people involved in such conversations who were not authorized to discuss the matter publicly.

But some career employees expressed fear that as the hearings continued, they would raise expectations for a prosecution that may not be met.

The committee “was good at making the case that Donald Trump’s actions were completely horrific and that he deserves to be held accountable for them,” said Matthew Miller, a former Justice Department spokesman during the Obama administration. “But an open-and-shut case on television is different from proving someone violated a criminal statute.”

With public attention fixated on Mr. Trump, the Justice Department’s work has proceeded along three tracks: charge the people who attacked the Capitol; piece together larger conspiracies, including sedition, involving some of the assailants; and identify possible crimes that took place before the assault.

Prosecutors are scrutinizing the plan by Mr. Trump’s allies to create alternate slates of pro-Trump electors to overturn Joseph R. Biden Jr.’s victory in key swing states, with a federal grand jury issuing subpoenas to people involved. That investigation brings prosecutors closer to Mr. Trump’s inner circle than any other inquiry.

No sitting or former president has ever been put on trial. Aaron Burr was charged with treason after leaving office as vice president in a highly politicized case directed from the White House by President Thomas Jefferson, but he was acquitted after a sensational trial. Ulysses S. Grant, while president, was arrested for speeding in his horse and buggy. Spiro T. Agnew resigned as vice president as part of a plea bargain in a corruption case.

The closest a former president came to indictment was after Richard M. Nixon resigned in the Watergate scandal in 1974, but his successor, Gerald R. Ford, short-circuited the investigation by preemptively pardoning him, reasoning that the country had to move on. Mr. Clinton, to avoid perjury charges after leaving office, agreed on his last full day in the White House to a deal with Mr. Ray in which he admitted giving false testimony under oath about his affair with Monica S. Lewinsky, temporarily surrendered his law license and paid a $25,000 fine.

Should the Justice Department indict Mr. Trump, a trial would be vastly different from House hearings in ways that affect the scope and pace of any inquiry. Investigators would have to scour thousands of hours of video footage and the full contents of devices and online accounts they have accessed for evidence bolstering their case, as well as anything that a defense lawyer could use to knock it down. Federal prosecutors would probably also have to convince appeals court judges and a majority of Supreme Court justices of the validity of their case.

For all of the pressure that the House committee has put on the Justice Department to act, it has resisted sharing information. In April, the department asked the committee for transcripts of witness interviews, but the panel has not agreed to turn over the documents because its work is continuing.

Although critics have faulted Mr. Garland, attorneys general do not generally drive the day-to-day work of investigations. Mr. Garland is briefed nearly every day on the inquiry’s progress, but it is being led by Matthew M. Graves, the U.S. attorney in Washington, who is working with national security and criminal division officials. Lisa O. Monaco, the deputy attorney general, broadly oversees the investigation.