The time to question election results has passed, and there is no role for the military in changing them, all 10 of the living former defense secretaries said in an extraordinary rebuke to President Trump and other Republicans who are backing unfounded claims of widespread fraud at the ballot box.

The former Pentagon chiefs issued their warning Sunday evening in an opinion piece that they co-wrote and published in The Washington Post. Its authors include Trump’s two former defense secretaries, Jim Mattis and Mark T. Esper, as well as each surviving, Senate-confirmed Pentagon chief dating back to Donald H. Rumsfeld in the 1970s.

The article was published as some Republicans plan to take the controversial step of contesting the electoral college vote certification on Wednesday, even after the president’s repeated attempts to challenge election results in court have failed. It also comes as concerns persist that Trump might seek to use the military to keep himself in office, despite his electoral loss.

“Our elections have occurred. Recounts and audits have been conducted. Appropriate challenges have been addressed by the courts. Governors have certified the results. And the electoral college has voted,” the former defense secretaries wrote. “The time for questioning the results has passed; the time for the formal counting of the electoral college votes, as prescribed in the Constitution and statute, has arrived.”

The White House did not respond to a request for comment about the article.

The article brings together a group of Republicans and Democrats who disagree on many national security issues. Its genesis is a conversation between Eric Edelman, a former U.S. ambassador and defense official, and former vice president and defense secretary Richard B. Cheney about how the military might be used in coming days, Edelman said in an interview.

Weeks before the 2020 presidential election, congressional Republicans said President Trump would accept the election result. (The Washington Post)

While Trump has called reports that he discussed the possibility of invoking martial law to overturn election results “fake news,” he did have Michael Flynn, a retired Army general and former national security adviser for Trump, at the White House recently after Flynn suggested on television that Trump could declare martial law and use the military to hold new elections.

Protests are expected in Washington on Trump’s behalf this week, and the president has encouraged his supporters to show up, tweeting: “Be there, will be wild!”

Edelman, who was among a group of Republicans who endorsed President-elect Joe Biden over Trump, said that after Cheney expressed interest in co-authoring an opinion piece, Edelman solicited participation from other former defense secretaries, and wrote a draft of the article along with Eliot Cohen, a former Republican national security official who is dean of the Johns Hopkins School for Advanced International Studies.

Some of the defense secretaries requested revisions, but nothing significant to the message, Edelman and Cohen said.

“I do think that once one signs, another might be more willing to sign. But I still think it’s pretty remarkable,” said Cohen, an expert on civil-military relations. “This is a fairly gutsy thing to do, and I give them a lot of credit for it.”

Chuck Hagel, a former Republican senator who crossed the aisle to serve as a defense secretary for President Barack Obama, said in an interview Sunday that he asked ahead of publication whether the piece would be an overreaction to a potential problem.

But he ultimately decided that it was wise to weigh in, citing a desire to remind those serving in the Defense Department of their responsibility to help ensure a peaceful transition of power.

“This is a fundamental element of our democracy, and it lands squarely in the responsibilities of defense officials,” Hagel said. “I thought, in the end, that this was something that was important that we do.”

William Cohen, who served as defense secretary under President Bill Clinton, said in an interview that the discussion of martial law alarmed him, especially after Trump’s use of the military and other federal forces to remove protesters outside the White House in June.

The former defense secretary also cited the use of federal law enforcement personnel to remove protesters in Portland, Ore., in unmarked vehicles as another abuse of power. While he said he has no doubts about the willingness of Gen. Mark A. Milley, the chairman of the Joint Chiefs of Staff, and other senior military officials to follow the law, he is concerned that violence started by Trump supporters such as the Proud Boys in coming days could be used as a pretext to use the military against civilians again.

“It’s a very dangerous course of action that needs to be called out before it happens,” Cohen said of using the military against civilians.

Other former defense secretaries either could not be reached for comment or declined to speak, citing a desire to let the article speak for itself.

In addition to stating their concerns about the ongoing contesting of the election, the defense secretaries backed recent comments from senior military leaders that there is no role for the military in determining the outcome of a U.S. election, a point they affirmed after Flynn suggested the president could invoke martial law.

“Efforts to involve the U.S. armed forces in resolving election disputes would take us into dangerous, unlawful and unconstitutional territory,” the defense secretaries wrote. “Civilian and military officials who direct or carry out such measures would be accountable, including potentially facing criminal penalties, for the grave consequences of their actions on our republic.”

The former Pentagon chiefs also called on acting defense secretary Christopher C. Miller and other Trump administration officials in the Pentagon to “wholeheartedly” facilitate a transition to Biden’s administration.

While some transition meetings were carried out in late November and December, Miller canceled others beginning Dec. 18, citing a backlog of work that senior Pentagon lawyers had.

“We call upon them, in the strongest terms, to do as so many generations of Americans have done before them,” the former defense secretaries said of the transition. “This final action is in keeping with the highest traditions and professionalism of the U.S. armed forces, and the history of democratic transition in our great country.”

Pentagon officials have said those transition meetings will begin again in a significant way this week, and denied accusations by Biden that his transition team had encountered “roadblocks” to needed information that smacked of “irresponsibility.” Among those meeting with the transition team this week are senior officers such as Gen. Austin “Scott” Miller, the top U.S. commander in Afghanistan, and Gen. Stephen Townsend, the top commander overseeing operations in Africa.

Mick Mulroy, a former defense official under Trump and ABC News analyst, said in a statement that the op-ed is “exceptional in its scope and its directness.”

“It needed to be,” Mulroy said. “I volunteered to assist with the transition as soon as I was asked. I am not a partisan person, but this is beyond partisanship. It is the duty of any American, especially those that gave an oath to the Constitution, to ensure the peaceful transfer of power to the duly elected President.”

Missy Ryan contributed to this report.