(CNN) When a group of moderate House freshmen Democrats moved from hard no to hell yes on starting an impeachment inquiry into President Donald Trump, they changed the dynamic for House Democrats, and indeed -- the course of history.

The reason they made their announcement and explained their reasoning as a group, in an op-ed in The Washington Post , is because they had already formed a bond over their national security background -- especially the five women: Elissa Slotkin of Michigan and Abigail Spanberger of Virginia, both ex-CIA officers; Chrissy Houlahan of Pennsylvania who was in the Air Force; Mikie Sherrill of New Jersey and Rep. Elaine Luria of Virginia were Naval officers.

They met on the 2018 campaign trail as first time candidates who kept bumping into each other at events with mutual donors and supporters.

When they got to talking, these five would-be congresswomen realized that they had a lot in common, despite being from different parts of the country: they all had careers in national security they were trying to parlay into elected office.

They became fast friends, and called themselves the "badasses."

"I think badasses kind of came organically from the group since we all had either served in the military or in the CIA," Houlahan said.

They are now a band of sisters who bonded while storming the unfamiliar terrain of politics.

"Being able to text folks and say, 'you know, I'm really getting hit up on this issue, how have you been handling it?' 'I'm not sure how to translate my service into something that's relatable. How do you guys do that?'" Slotkin said she frequently asked the others.

"We have a lot in common," said Spanberger. "We all were working to flip seats to be elected in places where voters may not typically vote for people like us or with our backgrounds."

Making their mark in an unlikely way: impeachment

When we first talked in mid-September, none of the five congresswomen women supported an impeachment inquiry. Then, after hearing Trump admit that he spoke to Ukraine's leader about Joe Biden , a potential 2020 political rival, they changed their minds. There is no evidence of wrongdoing by either Joe or Hunter Biden, and Trump himself has denied any wrongdoing.

"Having the sitting President of the United States, use leverage over a foreign leader to get dirt on an opponent," Slotkin said. "That very basic idea, I think cut for us, as national security people, just close to the bone."

The op-ed the women penned, along with Gil Cisneros and Jason Crow, two freshmen male veterans, opened the floodgates for others who had been resistant, and gave House Speaker Nancy Pelosi critical political cover as she announced a formal impeachment inquiry on Tuesday.

They say it was all for one, and one for all.

"A great example of the power of teamwork," Houlahan said.

"I think we all sort of came to that conclusion together," Sherrill said. "We text each other as you know, and I think we were all going, okay, I think this has all changed. This is a bright line."

Still, it was a big leap for people still trying to find their sea legs in politics.

"I'm supervising the operation nuclear reactor," Luria recalls of her time before being in office. "I never turned the reactor operator and said, are you a Democrat or Republican?"

"It was new to jump into such a partisan environment," she added.

From left to right, Rep. Chrissy Houlahan of Pennsylvania, Rep. Elaine Luria of Virginia, Rep. Mikie Sherill of New Jersey, Rep. Abigail Spanberger of Virginia and Rep. Elissa Slotkin of Michigan.

Top GOP targets

Backing an impeachment inquiry is risky political business for these congresswomen -- some of the biggest political targets in the House. They are Democrats who won mostly in Trump territory by campaigning on kitchen table issues like health care and affordable prescription drugs.

Their GOP opponents are already attacking them hard for backing an impeachment inquiry of a president who won in 2016 with considerable support in most of their districts.

"I believe that if I am out there explaining what these allegations are to the people of my district and to the people of other districts, and why they are so deeply concerned that the people will understand why we had to take a stand," said Spanberger, the first Democrat to represent her Virginia district since in almost 50 years, and where President Trump won by 7 percentage points.

They are under no illusion that this is going to be politically easy for them.

"All of us in our prior lives all the time had to make hard calls for the reasons we thought were right when we knew that not everyone would understand or even know," declared Slotkin, who also represents a district where Trump won by 7 percentage points. " And that to me is something I feel comfortable doing because I've always had to do it."

Change

CNN sat down with these self-described "badasses" in the House Armed Services Committee room on Capitol Hill, surrounded by portraits of all the men -- only men -- who have chaired the committee on which four of them now sit.

Houlahan noted that many of them, as well as rank-and-file members of this committee, historically did not always have previous military service on their resumes.

Luria and Sherrill -- both Navy veterans -- quickly agreed.

"You were on ships," said Houlahan, pointing to Luria. "I was an engineer."

"We were all, you know, kind of experiencing our service in different ways," Houlahan said. "And I think we're able to fold that in together on legislative ideas and our agendas."

"I did three tours in Iraq, alongside the military" added Slotkin a former CIA officer, "carrying a weapon and wearing my body armor. And I think there's something about having done prior service that connects you to the consequences of the decisions that are being made here and at the White House."

Not 'the squad'

Until now, the House freshmen group that got the most headlines is the so-called "squad," who come from reliably Democratic areas far different from the swing districts these "Badasses" represent.

They have different political realities, and very different styles.

"None of us is ever going to get in a Twitter war with anyone else," Slotkin said flatly. "If we have a concern with someone, we're going to go right up and talk to them about it and we're not going to add unhelpful rhetoric to an already bad tone coming out of Washington."

Have they been frustrated that "the squad" and Twitter wars they're involved in get attention?

"I don't care who has the headlines," Spanberger responded. "I care about the legislation that we prioritize and I don't think any of us want to be the loudest voice in the room. I just want to be one of the most effective."

They also realize that despite needing GOP votes to win these moderate districts, they also need to keep their left flank happy, and excited.

"What I tell people in my district, the left wing of our party has created such momentum behind things like moving forward on our environment," Sherrill said.

From left to right, Rep. Chrissy Houlahan of Pennsylvania, Rep. Abigail Spanberger of Virginia, Rep. Mikie Sherill of New Jersey, Rep. Elaine Luria of Virginia, and Rep. Elissa Slotkin of Michigan.

Bonding over job as well as family

They picked offices near one another, which they say makes it easier to work together -- in rarer moments than they anticipated -- decompress with a glass of wine of a bottle of beer.

They bond not just over their jobs, but their families. They all have children -- some, very young.

Spanberger has three daughters ages five, eight and eleven, and says her middle daughter wants to be Houlahan for Halloween.

"It's gonna be hard to pull off," Houlahan said, laughing.

Sherrill is a mother of four young children.

"Somebody said to me the other day, they said, 'well, you're just real down to earth. You're not, you know, you're pretty humble.' And I said, yeah, I have a 14-year-old daughter, It's really hard not to be humble," joked Sherrill.

Slotkin said that when she started running for Congress she was struck by how unusual it seemed for people that her husband was by her side as an active participant in her campaign.

"A lot of people would say, you guys are so modern ... I said, what? What does that mean?" she recalled.

"I realized after a few people said it, that they were used to either a man running for office and the wife is way in the background, you know, quiet, not a part of the campaign," Slotkin said. "Or there is a strong woman who's running, we've had strong women who have run and won, but their husband is nowhere to be seen. So when they saw a strong woman and a strong man together, that was new for them."

Breaking the chain of command

The "badasses" say that several more senior women in Congress have told them how much they marveled at how fearless they are in meetings and in hearings, considering how new they are to politics, never mind Congress.

"There's not a vertical chain of command structure," said Luria, noting the difference between Congress and the Navy where she served for 20 years.

When reminded that it may be less formal in Congress, but there historically is a wait-your-turn and know-your-place Capitol Hill dynamic, they collectively shrugged that off.

"None of us, none of us came to Congress from a district that wants us to just sit here and be quiet and learn the ropes and figure it out," Sherrill said. "They want us to engage and they want change and they want it now."

They are certainly getting it.