Reps. Barbara Lee and Elissa Slotkin are a generation apart and politically reside in very different wings of the Democratic Party.

The 73-year-old Californian, who hails from one of the 10 most liberal districts, has been leading the antiwar movement for decades. The 43-year-old Michigander, coming from a district President Trump won comfortably, spent almost 15 years working at the CIA, Pentagon and other national security posts, focused on Middle East policy.

On Thursday, Lee and Slotkin helped lead the opposition to Trump’s military actions against Iran over the last week, amid fears that fallout from the U.S. drone strike in Baghdad could spark a third war in the region.

They knitted together a once unthinkable coalition that stretched across almost the entire Democratic caucus, as just eight Democrats opposed the war powers resolution that passed one week after Trump ordered a lethal strike against an Iranian commander. Three Republicans and one independent supported the Democratic resolution.

Lee has come a long way since she cast the lone vote in Congress against the war resolution passed after the Sept. 11, 2001, terrorist attacks, at a time when everyone else rallied around a law that more than 18 years later would still be cited as the authorization for many military actions.

“Going back to 2001, it was very lonely, because I was the only one who voted against the authorization to use force, a blank check,” Lee recalled in an interview before Thursday’s vote.

This new Democratic majority demonstrated this week that it could unify the caucus, with Lee helping lead support for a resolution that Slotkin drafted.

“If our loved ones are going to be sent to fight in any protracted war, the president owes the American public a conversation,” Slotkin said during Thursday’s floor debate.

Within three days of the U.S. drone strike that killed Maj. Gen. Qasem Soleimani, the commander of Iran’s elite Quds Force, House Speaker Nancy Pelosi (D-Calif.) announced that Slotkin would take the lead on a war powers resolution meant to rebuke Trump’s handling of the situation.

Having taken a high-profile role supporting Trump’s impeachment last month, Slotkin had once again assumed a posture in a district where rallying around the flag and the president might be the safer political bet.

On social media and in emails to her colleagues, particularly many of the more than 60 freshman Democrats, Slotkin reached into years of expertise in the Middle East to explain why she believed Trump’s actions further destabilized the region.

On Tuesday, during the first votes of the new year, Rep. Jahana Hayes (D-Conn.) gave Slotkin a hug on the House floor. “So I just thanked her for being so explicit and explanatory and vocal and spelling out what this means and this is why, because that is her area of expertise,” Hayes explained later.

After Iran responded with an overnight missile attack on bases housing U.S. soldiers, the Democrats dug further in.

During votes Wednesday afternoon, Slotkin worked the House floor and courted both members of the Congressional Progressive Caucus, where Lee is a leader, and Rep. Matt Gaetz (R-Fla.), a close Trump ally who was with him at his Mar-a-Lago resort the night of the drone strike.

While he’s close to Trump, Gaetz hails from a libertarian wing of the GOP and, after a few tweaks in the resolution, Slotkin won him over even as he still praised Trump.

“I support the president; killing Soleimani was the right decision. But engaging in another forever war in the Middle East would be the wrong decision,” Gaetz said in a floor speech minutes before the vote.

His support for the nonbinding resolution falls in line with Sens. Mike Lee (R-Utah) and Rand Paul (R-Ky.), another pair with libertarian instincts who are working with Sen. Tim Kaine (D-Va.) and Senate Democrats on a more forceful resolution that would limit Trump’s powers to escalate the conflict with Iran.

But, for the most part, they remained outliers in the House and Senate GOP caucuses, where national security hawks still reigned.

And those Republicans pinned the Democratic response on national security to their loathing of Trump, whose impeachment trial in the Senate remains stalled over an impasse about whether to call witnesses.

“Not liking President Trump is not an excuse for failing to see that this president and his administration have a sensible — and deeply American — strategy for dealing with Iran,” House Minority Leader Kevin McCarthy (R-Calif.) said.

The shift on national security has come over a long period since the Sept. 11 attacks, as two different wars seemed to morph into one and from that came several other fronts that left most voters confused.

“The public has really begun to see the fact that these authorizations serve as the foundation, the basis for endless war, and the public is war-weary,” Lee said.

By 2002, in the run-up to the vote to approve war in Iraq to remove Saddam Hussein from power, a new member of Democratic leadership, Pelosi, rallied the opposition and got a narrow majority of her caucus to oppose the resolution, a symbolic victory that signaled her future ascension to take the Democratic reins of leadership.

Yet even after winning the speaker’s gavel in 2006 and an expansive majority in 2008, Pelosi oversaw a caucus that remained divided on how much leeway to give presidents, Republican or Democratic, with many newcomers hailing from conservative regions.

Some of Pelosi’s most divisive votes during her first stint as speaker came on bills to fund the wars in Iraq and Afghanistan, splitting the caucus as the GOP stood almost entirely unified.

By 2018, after Trump’s victory, Slotkin joined a group of national security experts to launch their first bids for office, helping propel Democrats back into the House majority. Still, for some, Thursday’s vote went too far — six of the eight Democrats who opposed it were among the freshman class, including two, Reps. Elaine Luria (D-Va.) and Max Rose (D-N.Y.), with military backgrounds.

Lee saw this debate as a first step, as only about 25 percent of the House members had actually been in office in 2001 and 2002.

Slotkin saw it as a step toward remedying a long-overdue debate. “Congress has long abdicated its responsibility as laid out in the Constitution to make the hard decisions we owe our troops,” she said.