WASHINGTON — A bipartisan group of young lawmakers with military or intelligence backgrounds has been in the forefront of the congressional response to the Jan. 6 attack on the Capitol, and the cadre played a central role since then in the second impeachment of President Donald Trump.

The group, which draws mostly from the Armed Services Committee, protected their fellow lawmakers during the attack. They also used military expertise to detect what they said were unnamed lawmakers who had possibly helped rioters plan their attack the day before.

They spoke of their oath to protect and defend the Constitution, in the military and in Congress alike, as they implored their colleagues to impeach Trump for his role in instigating the mob.

To be sure, all but 10 Republicans in the House, many of them military veterans as well, disagreed with the young cadre and voted not to impeach the president.

But the emergence of the bipartisan squad of military and intelligence veterans as key players in the lead-up to Wednesday's vote betokens a greater role for these members in Congress' future political and security debates.

Jason Crow, D-Colo., a second-term member of Armed Services who was an Army Ranger and served a tour in Iraq and two in Afghanistan, was among the leading members of this group.

House Minority Leader Kevin McCarthy, R-Calif., in a floor speech on the day of the riot, singled out Crow and a few other members for heroism in the face of the assault.

Crow, it turned out, had done everything that day from holding the hand of a panic-stricken Susan Wild, D-Pa., to being the last person to leave the gallery when members evacuated.

One week after the riot, Crow — who had been a manager of Trump's first impeachment — did battle with McCarthy during the second impeachment debate.

Crow couched impeachment as a matter of patriotic duty.

"Last week I stood in that gallery to defend this chamber against a violent mob called here by Donald Trump, and I have dedicated my life to the defense of our nation, and Donald Trump is a risk to all that I love," Crow said on the House floor. "Some of my Republican colleagues are afraid of the consequences of an impeachment vote. But this Congress sends our young men and women to war every day. I'm not asking you to storm the beaches of Normandy but only show a fraction of the courage we ask of our troops every day."

Among the 10 House Republicans who voted for Trump's second impeachment were two who had served their country in uniform: freshman Michigan Rep. Peter Meijer, an Army veteran who served a tour in Iraq, and Adam Kinzinger of Illinois, a former Air Force pilot who has been in Congress for a decade.

Meijer, in a statement posted to Twitter, said "the president betrayed his oath of office by seeking to undermine our constitutional process, and he bears responsibility for inciting the violent acts of insurrection last week."

Kinzinger, a member of the Foreign Affairs Committee who was one of the first Republicans to blame Trump for last week's violence, said in a statement that there was "no doubt in his mind that the president of the United States broke his oath of office and incited this insurrection."

But the group of military and intelligence vets in the forefront of last week's events was composed mostly of Democrats.

One was New Jersey Democrat Mikie Sherrill. Like Crow, Sherrill is a second-term member who serves on Armed Services. She was a Navy helicopter pilot and a former assistant U.S. attorney in her state.

Sherrill made news Jan. 12 when she said in a Facebook Live post that she saw certain unidentified members of Congress giving people tours of the Capitol the day before the riots in what she said appeared to effectively be "reconnaissance" missions.

Sherrill and 33 other members wrote a letter Wednesday to Congress's acting sergeants at arms and the acting head of the U.S. Capitol Police urging an investigation.

The members said the people on the tours appeared to be among those who attacked the Capitol.

"Many of the Members who signed this letter, including those of us who have served in the military and are trained to recognize suspicious activity, as well as various members of our staff, witnessed an extremely high number of outside groups in the complex on Tuesday, January 5," they wrote. "This is unusual for several reasons, including the fact that access to the Capitol Complex has been restricted since public tours ended in March of last year due to the pandemic."

The signatories on the letter included four other Democrats with military or intelligence backgrounds, including Ted Lieu of California, a former active-duty Air Force officer who still serves as a colonel in the Air Force Reserve and who is one of the managers of the case to impeach Trump a second time.

Also on the list were Democrats Abigail Spanberger of Virginia, a retired CIA operations officer; Elaine Luria of Virginia, a former Navy surface warfare officer and nuclear engineer; and former soldier Bill Pascrell Jr. of New Jersey.

In September 2019, Crow, Sherrill, Spanberger and Luria were among seven then-freshmen Democrats with national security bona fides who wrote a notable Washington Post oped calling for Trump's impeachment over his coercion of Ukraine's president for attempted political gain.

Luria was among the many members who spoke briefly on the House floor Wednesday. She didn't mention her Navy service, but her rhetoric evoked a battle.

"History will look back on this moment to see who stood strong in support of American democracy," Luria said.

Another signatory of that 2019 letter who has emerged as a pivotal player in the last week is Elissa Slotkin, who was a CIA officer in Iraq and a top official in the State and Defense Departments.

Slotkin, a Michigan Democrat, also serves on Armed Services and was another outspoken proponent of a second impeachment.

She was active on Jan. 6 in trying to get the Pentagon to send D.C. National Guard support for police defending the Capitol.

"What we saw yesterday was terrorism, plain and simple," Slotkin tweeted Jan. 7.

Amid reports that some of the rioters were current or former military personnel, Slotkin has remained outspoken about ensuring that those who wear the uniform stay out of politics — and certainly out of violence.

In an oped in the Detroit Free Press this week, Slotkin defended her position supporting impeachment by saying her "guiding principle" is that "there are simply some things that go beyond politics — and certainly beyond any one congressperson being reelected. And those things are matters of principle. They are about preserving the sacred rights afforded to each of our citizens in our founding documents."

Another leader of the impeachment drive who was by all accounts a hero on Jan. 6 was Arizona Democrat Ruben Gallego, an Armed Services member who served with the Marine Corps in Iraq.

Gallego reportedly helped other members with their gas masks as the attack was underway and then sheltered reporters in his office.

Spanberger, too, was said to have made efforts to make sure reporters had protection as the marauders approached.

"This vote represents a united response to a disgusting act of brutality and sedition — and today is a solemn moment in our nation's history," Spanberger tweeted shortly after the House voted to impeach Trump.