WASHINGTON — House Democratic leaders, their patience clearly fraying, signaled this weekend to Representative Alexandria Ocasio-Cortez’s outspoken top aide that his seeming efforts to lead an insurrection against more moderate Democrats would no longer be tolerated — a message also aimed at the freshman congresswoman who employs him.
Ms. Ocasio-Cortez, a liberal firebrand from the Bronx, has given her chief of staff, Saikat Chakrabarti, remarkable latitude to pursue the divisive politics that made his name when he led Justice Democrats, a group founded to challenge entrenched Democrats through primary campaigns.
With that license, Mr. Chakrabarti has become an unelected symbol of the party’s growing disunity, as Democrats try to coalesce as a party before what promises to be a punishing fight next year for the White House. The battle between the Democrats who secured the House majority last year by flipping Republican districts and the smaller, but politically potent, left-wing from secure Democratic districts has found its cause célèbre.
Mr. Chakrabarti ignited a firestorm two weeks ago after a bruising intraparty fight over an emergency border aid package that progressives said lacked sufficient restrictions on the Trump administration. Calling out moderate Democrats who sank a more liberal aid package, he compared them to “new Southern Democrats.”
They “certainly seem hell bent to do to black and brown people today what the old Southern Democrats did in the 40s,” he said on Twitter. He later deleted the tweet.
On Friday night, Democratic leaders showed that they had enough. Using the House Democratic Caucus’s official Twitter account, they delivered a rhetorical slap that questioned not only Mr. Chakrabarti’s future but also whether Ms. Ocasio-Cortez wanted to be a lawmaker on the inside or an outsider campaigning to purge the party of centrists and force it to the left.
The rebuke shared a tweet by Mr. Chakrabarti that explained that he believed Representative Sharice Davids of Kansas, one of the two first Native American women to serve in Congress, was enabling a “racist system” in voting for a weaker border aid package.
“I don’t think people have to be personally racist to enable a racist system,” the aide had written, to which Democratic leaders demanded,“Who is this guy and why is he explicitly singling out a Native American woman of color?”
The slap ended with, “Keep her name out of your mouth.”
That last phrase was filled with its own meaning. It echoed a blow delivered on Tuesday to the White House adviser Kellyanne Conway by Representative Ayanna S. Pressley of Massachusetts, a member of Ms. Ocasio-Cortez’s “squad,” who wrote, “Keep my name out of your lying mouth.”
To further make the point, Speaker Nancy Pelosi’s deputy chief of staff, Drew Hammill, retweeted the slap.
Mr. Chakrabarti, a former Silicon Valley start-up founder turned left-wing political organizer, has defiantly retained his outsider streak even after becoming a chief of staff at one of the nation’s most establishment institutions, the House. That has riled ranks of Democratic lawmakers and aides. While convention on Capitol Hill holds that aides are to be seen and not heard, he has publicly and repeatedly criticized Ms. Pelosi. Perhaps most galling to lawmakers, he has also encouraged his Twitter followers to support liberal candidates trying to oust sitting Democrats, an uneasy reminder of his work with Justice Democrats.
He has cultivated a remarkably high profile for a congressional aide. He “isn’t just running her office,” a Washington Post Magazine profile of him said, “he’s guiding a movement.” A headline from Elle magazine crowed, “You Need to Know Alexandria Ocasio-Cortez’s Chief of Snacks Saikat Chakrabarti.”
Mr. Chakrabarti has also remained defiant. He dismissed the rebuke from Democratic leadership Friday night, arguing that “Everything I tweeted 2 weeks ago was to call out the terrible border funding bill that 90+ Dems opposed.”
“Our Democracy is literally falling apart,” Mr. Chakrabarti tweeted. “I’m not interested in substance-less Twitter spats.”
Justice Democrats, the group he founded, and over a dozen other progressive groups backed him on Saturday, releasing a statement expressing concern that “senior Democratic Party leaders and their aides have been escalating attacks on new leaders in the party.”
The drama may be more reminiscent of a high school student council than the House of Representatives, but it has created a dilemma for Ms. Ocasio-Cortez. The progressive darling has remained silent on her aide’s remarks; her spokesman declined to comment on Saturday. Asked on Thursday to comment on her aide’s earlier tweets, Ms. Ocasio-Cortez replied that she had “not been paying attention to this.”
That is likely to further anger House members, many of whom are people of color representing moderate to conservative districts. It is considered a breach of protocol for unelected congressional aides to criticize lawmakers even in closed-door meetings — much less publicly blast out their grievances — and those who step out of line typically face consequences.
As the chairman of a powerful conservative caucus, Representative Steve Scalise of Louisiana, the No. 2 Republican, fired a top aide in 2013 after allegations that the aide had allied with conservative advocacy groups to blow up a Republican leadership budget deal.
“We all rely on staff, but we have to have the full trust of our staff,” Mr. Scalise said at the time.
But Ms. Ocasio-Cortez prides herself on eschewing convention — an instinct that guided her ascent to become the youngest-ever elected representative — and so far has extended that approach to her staff. Shortly after arriving to Capitol Hill, her legislative assistant, Dan Riffle, gave an interview in which he described fellow Democratic congressional aides as Ivy League “careerists” who “don’t think big and aren’t here to change the world.”
Mr. Chakrabarti also has unloaded his grievances, sparing no one.
“Pelosi claims we can’t focus on impeachment because it’s a distraction from kitchen table issues. But I’d challenge you to find voters that can name a single thing House Democrats have done for their kitchen table this year,” Mr. Chakrabarti wrote after the divisive vote on border aid. “What is this legislative mastermind doing?”
“I like to show my cards and see people’s reactions,” Mr. Chakrabarti told The Washington Post Magazine, echoing President Trump. But other controversies have dogged him — in part because of the outsize attention Ms. Ocasio-Cortez receives from right-wing news outlets — for a lack of forthrightness.
After graduating from Harvard, Mr. Chakrabarti worked for a year as a technology associate at the hedge fund Bridgewater Associates, and then moved to Silicon Valley to help found the technology company Stripe. He is presumed to be rich, but has not filed a financial disclosure form, leadership aides say.
Because Ms. Ocasio-Cortez capped her senior aides’ salaries to ensure she could offer an entry-level wage of $52,000, her employees are below the income threshold that mandates public financial disclosure. Instead, a House ethics panel required her to compel at least one of her aides who can “act in the member’s name or with the member’s authority” to file a disclosure form.
Ms. Ocasio-Cortez chose Mr. Riffle, the legislative assistant, to submit the disclosure, rather than Mr. Chakrabarti.
In March, a conservative group filed a complaint with the Federal Election Commission saying that Mr. Chakrabarti improperly disclosed the spending of two political action committees he helped establish that paid more than $1 million in 2016 and 2017 to a company he ran.
The company, Brand New Congress L.L.C., was an arm of a group he helped found by the same name that recruited community organizers as candidates who would all adopt the same transformative progressive platform; in turn, the group would contract their staff out to help run the candidates’ campaigns. To do this, Brand New Congress argued, the group had to be set up as a limited liability company — which is not required to disclose information about its owners or spending.
A lawyer for the company has said that Mr. Chakrabarti never received any salary or profit from the company, the political action committees or the campaign, and that the move was legal.