First, the freshman's chief of staff compared more centrist Democrats to 1940s segregationists. Then Ocasio-Cortez, D-NY., accused Speaker Nancy Pelosi of "singling out" her and fellow newcomers, all women of color.
By Thursday, the rhetoric escalated, overshadowing the agenda and pushing House Democrats way off message with the most divisive upheaval since they took control of the chamber this year. Longtime lawmakers were stunned.
"How dare they try to play the race card at this point," said Rep. William Lacy Clay, an African-American Democrat from Missouri who faces a primary challenge backed by allies of Ocasio-Cortez. He called those making the claims "ignorant" of racial history. "It shows the weakness of their argument. It's damaging to this party and the internal workings of the Democratic party."
Rep. John Lewis, the Civil Rights icon, shared his view.
Lewis said it was "a little too far" for the staff member to compare lawmakers to segregationists.
"We all must work together, pull together for the country's good," the Georgia Democrat said in an interview. "The great majority of the caucus membership tends to work together and get along. We need to go forward, not backward."
The problems have been developing for weeks, mounting as Congress struggled to pass a border funding package, but now may force a reckoning among Democrats that spills beyond Capitol Hill and into the 2020 campaigns.
Late last month, tensions grew between liberals, including Ocasio-Cortez and the "squad" of three other freshmen, and centrists from the Problem Solvers, Blue Dog and New Democratic caucuses over protections for migrant children and families in detention. With time ticking before funding ran out - and lawmakers set to leave town for the July 4th holiday - centrists revolted, forcing Pelosi to drop liberal demands and approve a more modest Senate version of the bill.
And then the fallout began.
"Didn't realize this needed to be said, but: you can be someone who does not personally harbor ill will towards a race, but through your actions still enable a racist system. And a lot of New Democrats and Blue Dogs did that today," tweeted Saikat Chakrabarti, the chief of staff for Ocasio-Cortez. It was an extraordinary attack by a staff member on elected officials.
"This is in reference to my comparing Blue Dogs and New Democrats to 1940s Southern Democrats," he wrote in another. "Southern Democrats enabled a racist system too. I have no idea how personally racist they all were. And we're seeing the same dynamic play out now."
That weekend, in trying to tamp down the divisions, Pelosi dismissed the influence Ocasio-Cortez and the squad - Reps. Ilhan Omar, D-Minn., Ayanna Pressley, D-Mass., and Rashida Tlaib, D-Mich. - in a Sunday newspaper column. But it seems to have only enhanced their stature.
Allies of the foursome swiftly came to their defense, suggesting Pelosi was marginalizing the women of color who are the new face of the party. Chakrabarti tweeted his own critique of Pelosi.
Ocasio-Cortez told The Washington Post on Wednesday that "the persistent singling out ... it got to a point where it was just outright disrespectful ... the explicit singling out of newly elected women of color."
In a fundraising email Thursday, Justice Democrats, the progressive group that recruited Ocasio-Cortez to run for office, criticized Pelosi for "singling out four new leaders who are progressive women of color." The group is backing a handful of primary challengers to congressional Democrats, aiming for 25.
On Capitol Hill, the centrists got to work. Aides were quick to point out the co-chairwoman of the Blue Dog Coalition, Rep. Stephanie Murphy, is a refugee and the first Vietnamese-American woman elected to Congress. Two members of the coalition are African American lawmakers who lived through segregation. One of the members of the New Democratic Coalition, Rep. Terri Sewell, who is African-American, represents her hometown, Selma, Ala., as well as Montgomery and Birmingham, Alabama, and had reached out multiple times to Ocasio-Cortez after the tweets, to no response.
"I personally experienced Dixiecrats' bigoted policies growing up," Sewell said in a statement. "So, to even insinuate that I, or any other member of the New Dems, would promote policies that are racist and hateful or ones that would negatively impact communities of color is deeply offensive and couldn't be further from the truth."
Rep. Lou Correa, D-Calif., another co-chairman of the Blue Dogs and member of the Congressional Hispanic Caucus, said he has warned his staff off such actions. "It's sad, it's very sad."
One freshman, Rep. Mikie Sherrill, who won what had been a Republican-held seat in New Jersey, said the centrist lawmakers "work really hard to build broad coalitions. When people in the progressive wing of the party disagree, I do feel like they're not kind of lining up their sights on the right target."
Progressives and those allied with the Ocasio-Cortez and the squad wanted to shift the debate.
"Can we just talk about the issues we're dealing with? We have kids in cages," said Rep. Pramila Jayapal, D-Wash., co-chair of the Congressional Progressive Caucus, who said she was frustrated by the ongoing situation. "It's not about AOC. ... It's about progressives and our relationship to the Democratic caucus and our priorities."
Pelosi said she had been unaware of the tweet it until lawmakers brought it to her attention "some almost crying, some very upset and angry."
She spoke at length on the turmoil during a private meeting of House Democrats this week and on Thursday said she was done talking about her relations with Ocasio-Cortez and the others.
"They took offense because I addressed, at the bequest of my members, an offensive tweet," she said.
"How they're interpreting and carrying it to another place is up to them, but I'm not going to be discussing it any further."
Associated Press writer Alan Fram contributed to this report.
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