John Fetterman’s top aide repeatedly attacked Democrats Manchin, Sinema, Feinstein on Twitter

Sen.-elect John Fetterman’s, D-Pa., incoming chief of staff is an outspoken progressive who has time and again publicly criticized moderate Democratic Sens. Joe Manchin, Kyrsten Sinema and Dianne Feinstein.

Adam Jentleson — who previously worked in top roles for former Senate Majority Leader Harry Reid, D-Nev., and for multiple liberal organizations — attacked the Democrats for issues ranging from supporting the filibuster to opposing court packing.

In a January tweet, Jentleson lauded Fetterman for “running as a better Democrat than Joe Manchin,” calling it a “smart strategy” and a “good way to unite the party and bridge the lefty-normie divide.”

Last year, after months of party infighting, when Manchin said he would not support Biden’s multitrillion Build Back Better bill, Jentleson accused Manchin of “negotiating in bad faith this whole time.”

In February 2021, when Manchin said he would oppose Biden nominee Neera Tanden to lead the Office of Management and Budget, Jentleson slammed the decision as the “cheapest, lamest brand of performative bipartisanship.”

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In January 2017, just days before former President Donald Trump took office, Jentleson accused Manchin of “using the fact that he’s nominally a Democrat and in Senate leadership to generate headlines that help Trump.” 

Jentleson repeatedly called for packing more seats on the Supreme Court and eliminating the filibuster, so much so that he wrote a book about it last year titled, “Kill Switch: The Rise of the Modern Senate and the Crippling of American Democracy.”

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“If you want to know why Sinema is wrong about everything, from her false history of the filibuster to the inaccurate idea that it promotes bipartisanship and stability, I have a book to recommend,” Jentleson tweeted Jan. 13, linking to his book.

In October 2021, Jentleson fired off a pair of tweets calling Sinema a “bad knockoff” of the late Republican Arizona Sen. John McCain because of her refusal to support ending the filibuster.

“McCain opposed his party on issues where the GOP position was unpopular, most notably campaign finance,” he wrote. “He took the popular stance, which pitted him against big money. He also had years of credibility on the issue. Sinema is doing the opposite of that – and leaving a paper trail.”

Jentleson also accused Sinema of working to thwart President Biden’s agenda.

“Much of the case against Sinema is stuff that will hurt her in a general election, too,” he tweeted Oct. 14, 2021. “She has an incredible talent for finding innovative ways to show her constituents in AZ that she doesn’t give a damn about them. The “F— off” ring, the Euro trip… The ads write themselves.” 

“Sinema is not generating this kind of opposition because she’s blocking lefty priorities,” Jentleson tweeted Sept. 25, 2021. “She is gutting and undermining Biden’s agenda, and hurting all Dems including Mark Kelly. Rs are having a field day using her stances to hit him. His seat could decide the majority in 2022.” 

“For decades, self-avowed white supremacists used the filibuster to block voting rights bills,” he tweeted July 1, 2021. “Today, Sinema is defending the filibuster even as it is used, yet again, for the same purpose. Sinema is complicit in blocking voting rights bills, and this will be her legacy.”

Jentleson’s new boss, incoming Sen. Fetterman, repeatedly faced questions over his fitness to serve in the Senate due to cognitive issues he suffered from a recent stroke. It’s notable, given that Jentleson joined in progressive calls last summer to examine Feinstein’s mental fitness to serve in the Senate.

“Hopefully this is just noise, but it underscores why we are probably very foolish not to be having an open and honest conversation about Senator Dianne Feinstein’s fitness to serve,” he tweeted in July 2021.

Jentleson penned an op-ed for the New York Times in September 2020, days after Ruth Bader Ginsburg’s death, calling on Democrats to brand Supreme Court Justice Amy Coney Barrett’s nomination as “illegitimate” in order to pave the way for eventually eliminating the filibuster and packing more seats on the court.

“There’s no downplaying the suffering [Coney Barrett] can cause from the bench,” Jentleson tweeted that October, adding that “Feinstein demonstrably failed” to hold Senate Republicans accountable during the Barrett’s confirmation.

“The hearings were a mess but that’s on Feinstein,” he added.

Fetterman hired Jentleson, who has been advising the incoming senator during his transition, to be his chief of staff, Politico reported Friday. Jentleson was most recently the executive director of the Battle Born Collective, a progressive consulting group he founded, and had also recently worked for left-wing groups Democracy Forward and Center for American Progress.

Fetterman has previously said he does not support expanding the Supreme Court, and campaign spokesman Joe Calvello reiterated that to Fox News Digital for a separate story Sunday.

“John Fetterman is his own man with his own views; there is no one else like him in the U.S. Senate,” Calvello said. “John is deeply proud of the team he is putting together for his Senate office and is keen on creating a team with diverse views and backgrounds so they can fully serve the people of Pennsylvania. This should not be hard to understand.”

Fox News Digital’s Thomas Catenacci contributed to this report.