President Trump has intensified efforts to overturn the election, raising a series of radical measures in recent days, including military intervention, seizing voting machines and a 13th-hour appeal to the Supreme Court.

On Sunday, Trump said in a radio interview that he had spoken with Sen.-elect Tommy Tuberville (R-Ala.) about challenging the electoral vote count when the House and Senate convene on Jan. 6 to formally affirm President-elect Joe Biden’s victory.

“He’s so excited,” Trump said of Tuberville. “He said, ‘You made me the most popular politician in the United States.’ He said, ‘I can’t believe it.’ He’s great. Great senator.”

Tuberville’s campaign did not respond to a request for comment on Trump’s statement, which the president made in an interview with Rudolph W. Giuliani, his personal lawyer, on New York’s WABC radio station.

The Fix’s Aaron Blake analyzes how the dynamic between President-elect Joe Biden and congressional Republicans could play out in 2021. (The Washington Post)

Trump’s conversation with Tuberville is part of a much broader effort by the defeated president to invalidate the election. He is increasingly reaching out to allies like Giuliani and White House trade adviser Peter Navarro for ideas and searching his Twitter feed for information to promote, according to Trump advisers, who spoke on the condition of anonymity to discuss private conversations.

On Friday, Trump met with Giuliani and disgraced former national security adviser Michael Flynn, among others.

Flynn had suggested on Newsmax that Trump could authorize the military to rerun the election. “He could order the, within the swing states, if he wanted to, he could take military capabilities, and he could place those in states and basically rerun an election in each of those states,” Flynn said.

President Trump spoke at a rally on Dec. 5 to urge people to vote for Republican Sen. Kelly Loeffler and Sen. David Perdue ahead of the runoffs on Jan. 5. (The Washington Post)

The next day, Flynn was in the Oval Office to discuss the idea. Flynn’s attorney, Sidney Powell, who has promoted outlandishly false claims about this year’s election, including a disproved allegation that Venezuelan communists programmed U.S. voting machines to flip votes for Biden, was also in the meeting.

Officials inside the White House said Chief of Staff Mark Meadows and White House counsel Pat Cipollone pushed back “strenuously” on the idea of martial law. Two officials, who like others for this story spoke on the condition of anonymity to discuss private matters and conversations, said that there have been no efforts inside the White House to actually deploy the military and that the idea was quickly dismissed at the meeting.

Experts also agree the president does not have the authority to order such an action.

Meadows and Cipollone did not respond to requests for comment.

Trump also suggested naming Powell as special counsel on voter fraud, an appointment that appeared to be a non-starter.

“The fact that she’s in there, it’s totally nuts,” a senior campaign official said, referring to Powell. A second official noted that Matt Morgan, a lawyer for the Trump campaign, told employees Saturday that they should preserve records related to Powell. Dominion Voting Systems has threatened to sue Powell and the Trump campaign for what it described as “wild, knowingly baseless and false accusations.”

At the meeting, Trump again suggested that homeland security officials should seize state voting machines and investigate alleged fraud.

Acting homeland security secretary Chad Wolf and other homeland security officials have previously told the White House they have no authority to do so unless states ask for inspections or investigations, and they have not.

DHS officials were not present for Friday’s meeting and have not had subsequent conversations with the White House. Ken Cuccinelli, acting deputy secretary of homeland security, also told Giuliani in a call last week that they could not take the machines, said officials.

In recent days, Trump has expressed frustration that his Cabinet is not doing more to assist. At a Cabinet meeting last week at the White House, Trump vented about the election and made unsubstantiated allegations of fraud, officials said, but did not give Cabinet members specific orders. The president has said Wolf should have moved more quickly to fire Christopher Krebs, the former director of the Cybersecurity and Infrastructure Security Agency, after Krebs countered Trump’s claims of widespread election fraud.

Additionally, some of Trump’s advisers have convinced him that Attorney General William P. Barr has not done enough to investigate the claims of voter fraud, and the president has increasingly complained about him, they said.

On Sunday, the Trump campaign said it was filing a suit with the Supreme Court over Pennsylvania’s mail-in voting rules. The U.S. Supreme Court has twice declined to take up challenges to the Pennsylvania Supreme Court’s decisions regarding the state’s voting procedures. Generally, the court does not get involved in state court decisions on state law.

Efforts to persuade Trump to do a valedictory tour for some of his accomplishments, or focus on the coronavirus vaccine, have been futile, said two advisers. Advisers say they hope Trump going to Mar-a-Lago this week will calm his anger about the election, but Trump has shown no signs of pulling back.

Public officials and military leaders have refused to be drawn into Trump’s post-election maneuvering. On Friday, Army Secretary Ryan McCarthy and Gen. James C. McConville, the Army’s top officer, released a joint statement that said: “There is no role for the U.S. military in determining the outcome of an American election.”

Acting defense secretary Christopher Miller, who was installed after the post-election firing of Mark T. Esper, was not present at the meeting Friday night at the White House, a senior U.S. official said. Neither was Army Gen. Mark A. Milley, the chairman of the Joint Chiefs of Staff, who was traveling in the Middle East last week.

In recent days, Milley has stressed that the U.S. military will follow U.S. law, without directly criticizing the president or his most partisan supporters.

“We are unique among militaries,” Milley said in a Nov. 12 speech at the new National Museum of the United States Army. “We do not take an oath to a king or a queen, a tyrant or a dictator. We do not take an oath to an individual. No, we do not take an oath to a country, a tribe or a religion. We take an oath to the Constitution.”

Peter D. Feaver, a former member George W. Bush’s presidential administration who now studies civil-military relations at Duke University, said it was “extraordinarily distressing” that Flynn, a former national security adviser, would recommend to Trump that he do something “manifestly illegal and manifestly unconstitutional.”

“To invoke the Insurrection Act now to prevent that from coming to full fruition, there is just not basis for it,” he said. “The professional military ethics of it are pretty clear: The military is trained to not carry out illegal orders.”

The Justice Department also has not acquiesced to Trump’s pressure campaign to appoint special counsel to explore his unfounded claims of fraud, though officials say privately they are worried about what might transpire in coming weeks, as the president becomes increasingly desperate.

After the election, the Justice Department greeted Trump and his allies’ claims of grand election fraud mostly with silent skepticism. Barr loosened longtime Justice Department restrictions that might discourage prosecutors from publicly investigating fraud before results were certified, sparking internal and external outcry that he was seeking to bolster Trump’s contention that the election was stolen. But even then, officials found no evidence to support the idea that there was fraud that might have changed the election’s outcome, and no new cases were announced.

Then, early this month, Barr told the Associated Press that he had “not seen fraud on a scale that could have effected a different outcome in the election,” undercutting the president. Although Barr noted the department had examined some allegations of fraud, he seemed to specifically rebut one particular claim by Powell, who alleged a grand conspiracy in which election software changed votes.

Barr and Trump’s relationship already had been deteriorating, and the two men had “barely spoken” in the months before, people familiar with the matter said.

Last week, Barr submitted a resignation letter to Trump, revealing he would be leaving the department on Dec. 23. Though he heaped praise on Trump on his way out — and Trump in turn claimed, “our relationship has been a very good one” — the move seemed tied to the simmering tension between the two. Barr had wanted to stay on in a second term if Trump had won.

Starting on Wednesday, leadership of the department will fall to Jeffrey Rosen, who had been Barr’s top deputy. Rosen had been serving as a deputy transportation secretary before he was tapped to be the No. 2 Justice Department official under Barr. He had not worked at the Justice Department before, and some lawmakers questioned whether he had adequate experience for the job.

Rosen declined to answer questions in a recent interview with Reuters about whether he would name special counsels to investigate voter fraud or Hunter Biden.

Trump’s efforts to persuade congressional Republicans to question the legitimacy of the vote seem to be gaining traction.

Some current and incoming Republican members of the House, including Rep. Matt Gaetz (R-Fla.) and Reps.-elect Marjorie Taylor Greene (Ga.) and Barry Moore (Ala.), have suggested they will join Rep. Mo Brooks (R-Ala.) in using an 1880s law that allows members of Congress to dispute a state’s results and make the House and Senate vote on the challenge to the electoral vote tally on Jan. 6.

The effort is certain to fail in the Democratic-led House and will meet resistance in the Senate, where several Republicans, including Senate Majority Leader Mitch McConnell (R-Ky.), have dismissed the idea. Both chambers would have to vote in favor of any challenge for it to succeed.

Last week, while campaigning for Sens. Kelly Loeffler and David Perdue (R-Ga.) in Georgia, Tuberville suggested he would support an electoral vote challenge.

“You see what’s coming. You’ve been reading about it in the House. We’re going to have to do it in the Senate,” Tuberville said, according to a video posted online by liberal activist Lauren Windsor.

Tuberville did not say whether he would bring such a challenge himself. But in a speech to conservative activists Sunday, Gaetz said he had spoken with Tuberville and confirmed that the Alabama Republican plans to challenge the results.

“He says, ‘We are done running plays from the establishment’s losing playbook. It is time to stand and fight,’ ” Gaetz said at an event in West Palm Beach, Fla., sponsored by Turning Point USA, a conservative youth organization. “The odds may be tough, it may be 4th and long, but we’re going for it on January 6.”

Robert Barnes in Washington and David Weigel in West Palm Beach, Fla., contributed to this report.