Pentagon leaders are bracing for any renewed presidential attempts to employ the military for political ends, as President Trump takes increasingly aggressive steps to overturn his electoral defeat, and unarmed National Guardsmen prepare for pro-Trump protests in Washington on the day Congress is set to certify the election results.

Top Pentagon officials, in answering a request by D.C. Mayor Muriel E. Bowser (D) to deploy National Guardsmen in the nation’s capital in advance of Wednesday’s protests, emphasized that the Guard wouldn’t carry firearms, use armored vehicles or helicopters, or receive backup from units in other states — a far more muted presence than in June after the Minneapolis police killing of George Floyd.

The careful posture reflects the Pentagon’s wariness in the final days of a presidency during which Trump has tested the norms of a politically impartial military. It also comes after all 10 living former U.S. defense secretaries published a joint open letter warning that the military shouldn’t play a role in determining the election outcome or interrupt a peaceful transition.

Concerns that Trump may reach for the military to retain power as he enters the final chapter of resistance to the election’s result have grown sharper in recent days, partly after his former national security adviser, retired Army Lt. Gen. Michael Flynn, floated a declaration of martial law and a “rerun” of the election overseen by the military in a mid-December Oval Office meeting — a suggestion Flynn also has made publicly in the media. Trump, meanwhile, pressured Georgia’s secretary of state to “find” 11,780 votes he needs to win the state.

“It’s the fear that you are not dealing with someone who recognizes any responsibility to the Constitution. His only responsibility, from this president’s point of view, is to himself,” former defense secretary Leon Panetta said in an interview, when asked about the rationale for the letter. “When you operate on that basis, there’s no holds barred as to what a president may do. It is that scenario that scares the hell out of people in terms of the future of our democracy.”

One day before Congress votes to certify that Joe Biden won the presidential election, Trump supporters on Jan. 5 gathered in Washington to protest the results. (The Washington Post)

Current and former top officials said they believe the Pentagon brass has considered the possibility that Trump will issue a legally questionable order as part of his gambit to overturn the election results and prevent President-elect Joe Biden from entering the White House.

A senior U.S. official said Tuesday that the Pentagon senior leadership — civilian and military — will not obey an unlawful order from the president to use the military to his own political ends.

These leaders likely would resign before following an unlawful order, the senior official said, adding, however, “I think it’s unfair to assume that the president would issue an unlawful order.”

But Trump’s effort to overturn the election results has been so norm-shattering that senior Pentagon officials are being forced to consider the possibility of receiving orders that previously would have been unthinkable from a sitting U.S. president.

“In a real way, generals are paid to worry about everything. So while I really don’t expect the military to be asked to do anything truly questionable, it’s always best to expect the unexpected and prepare accordingly. My bet is that they have their lawyers at the ready,” said Charlie Dunlap, a retired Air Force major general and executive director of the Center on Law, Ethics and National Security at Duke University.

Since taking office, Trump has repeatedly flouted norms governing presidential interactions with the military, signing his ban on travel from majority-Muslim nations at the Pentagon, diverting Pentagon funds to pay for his border wall, treating troop events like campaign rallies and intervening in military justice matters. Some of his orders to the Pentagon, such as the holdup of congressionally approved military aid to Ukraine and the diversion of military funds to construct the border wall, have later been deemed illegal.

Peter Feaver, a scholar of civil-military relations and a colleague of Dunlap’s at Duke, said current Pentagon leaders were better prepared to handle any attempts to pull them into the transition because of the events of June 2020, when Trump sought to use expansive military force to put down widespread protests over police violence against Black citizens.

Then-Defense Secretary Mark T. Esper and Gen. Mark A. Milley, chairman of the Joint Chiefs of Staff, argued behind the scenes against invoking the Insurrection Act to allow Trump to employ active-duty troops in the nation’s capital. But they came under intense criticism over public statements and appearances that seemed to support Trump’s heavy-handed response to civilians in the streets, which included the use of tear gas and rubber pellets to disperse protesters near the White House before Trump posed for photos with a Bible in front of St. John’s Church.

In the subsequent months, officials have tightened procedures for employing the National Guard in an effort to reduce the likelihood of the White House calling in active-duty forces, and senior officials have repeatedly affirmed the military’s duty to remain loyal to the Constitution rather to any individual and decline any illegal orders. They have also studied relevant laws and assembled the capability to track civil unrest across the country to better prepare them for possible White House requests.

The senior U.S. official said the military leadership had learned from what happened last June. “Everyone has got a lot of scar tissue and a lot of PTSD from the domestic unrest of the summer” and does not want a repeat, the official said.

On Wednesday, the official said, the Pentagon hopes to make clear that the Guard is only serving as “traffic control” without guns, military vehicles or helicopters to aid the local police in Washington and steer clear of flashpoint areas.

“We’ve learned our lessons and will be absolutely nowhere near the Capitol Building,” the senior U.S. official said, adding: “We don’t want to send the wrong message. This is allowing the police to be able to do their jobs.”

Still, U.S. law grants broad powers to the commander in chief, particularly if the president finds reason to declare a state of emergency, as Trump did on the southern border to divert Pentagon funding to his border wall project. And Trump retains command of the D.C. Guard, because the District is not a state, as well as the power to relieve senior officials at will.

“Things like the Insurrection Act and the general authorities of the president as commander in chief — there is room here for a president to abuse his responsibility in this area,” Panetta said. “I think all of us can argue that the military has absolutely no role in determining elections, or for that matter in doing what law enforcement is responsible for doing in this country.”

Pentagon leaders have also sought to keep a mostly low profile on political issues. When Esper, who was fired by Trump in November, traveled overseas in the months before the election, he remained tightly focused in public comments on security matters, even as his diplomatic counterpart, Secretary of State Mike Pompeo, appeared at the Republican National Convention and freely made political remarks.

After Flynn suggested declaring martial law and using the military to “rerun” the election, Army Secretary Ryan McCarthy and Gen. James McConville, the Army chief of staff, issued a stark response: “There is no role for the U.S. military in determining the outcome of an American election.”

Feaver said he believed that senior officials, including Milley and acting defense secretary Christopher C. Miller, were right to remain mostly silent on political-related matters, if only because speaking out might provoke an unwanted action from Trump.

“Right now the president is focusing his attention on other things, and so if they were too prominent in the public, they would attract the Eye of Sauron in a way that would not be helpful,” Feaver said.

How Miller might respond to a request from Trump is unclear. A retired Army colonel, Miller comes from the secretive worlds of counterterrorism and Special Operations, and his policy views are largely unknown. Trump tapped him as acting Pentagon chief after falling out with Esper, who had objected to using active-duty military on U.S. streets in June.

Retired Adm. James Stavridis, who served as supreme allied commander of NATO, said that while the former defense secretaries’ appeal was remarkable, current defense leaders needed to speak out, too.

“What is needed is more clear guidance from the most senior levels in the Pentagon,” he said in an email to The Washington Post, singling out Miller. “The Acting SECDEF in particular should issue a direct statement echoing what [Milley], Secretary of the Army, and Chief of Staff of the Army have all said: there is no role for the military in resolving any election controversies.”

The events in June served as a wake-up call to many top officials at the Pentagon and in Congress about Trump’s willingness to reach for the military to advance his personal and political interests. In the most recent defense policy bill, Congress passed a law requiring all federal troops or law enforcement officers to wear uniforms showing their names and agencies, after federal agents under the Justice Department deployed this summer without insignia.

Sen. Chris Murphy (D-Conn.), who worked on the law, sent a letter Tuesday to the heads of the Defense Department, the Army and the Justice Department reminding them of the requirement.

“I have faith that our military chain of command will not stand in the way of a peaceful transition of power,” Murphy said Tuesday in an interview. “But there certainly is a risk that the president is going to put the military chain of command in the uncomfortable position of refusing to blockade Joe Biden from entering the White House.”

Murphy added, “It’s not good for democracy if they are in a position where they have to refuse the commander in chief.”

Former defense secretary William J. Perry, one of the ex-Pentagon bosses who signed the letter this week, said the joint statement was meant to stiffen the resolve of Pentagon leaders should Trump order them in any way to help him retain power.

“I know that our military is very disciplined, but they also have been trained to obey orders, and the two civilians who can order them are the secretary of defense or the president,” Perry said.

“I believe there could be real ambiguity in the minds of the military in what was legal and what was not legal, especially if the order is coming from the president,” Perry added in an interview.

Military law to a large degree incentivizes personnel to obey orders, which poses a dilemma when the lawfulness of an order is difficult to determine. Dunlap said the law allows military subordinates to presume an order to be lawful unless it is patently illegal — and “simply because an order is unwise or ill-considered doesn’t make it illegal.”

Murphy said there is “a lot less ambiguity around military intervention in the transfer of power from one president to another than there is in other kinds of orders from the president with questionable legal backing.”

“Trump is not terribly good at subtlety,” Murphy added, suggesting any order in this regard might not fall into a gray area. “I think he is more likely to ask them to do something blatantly unconstitutional.”