During a recent interview with CNN host Dana Bash, O'Brien fired back at AOC, saying that she was out of touch with her constituents given that a significant number of Teamsters in her district supported former President Donald Trump.

"[Ocasio-Cortez] should maybe get into her district, where it voted far-right Republican, and maybe find out what the problem is," O'Brien said. "In our polling, New York, her district, voted overwhelmingly Republican to support former President Trump, so she may want to focus on her job instead of mine."

The three-term congresswoman responded to O'Brien's comments in a separate tweet on Thursday, posting a press release from the Teamsters Local 202 union — which is the flagship Teamsters shop in her district representing roughly 7,500 workers and retirees – endorsing Harris. The union praised Harris for her record on "pension relief, changes to the National Labor Relations Board, infrastructure investment [and] supporting the Protect the Right to Organize (PRO) Act."

"The NY-14 Teamsters mentioned here have actually voted overwhelmingly to endorse Harris-Walz. Just as Teamsters in Michigan, Nevada, and Pennsylvania have, too. It’s a big thing to be wrong about," AOC tweeted in bold text. "So let’s set the record straight: Teamsters Local 202 are all in for Harris."

Aside from the Bronx Local 202 shop, various Teamsters councils throughout the U.S. representing approximately one million members have also endorsed the vice president's 2024 candidacy. Harris campaign spokeswoman Lauren Hitt tweeted a statement Thursday with the names of all of the Teamsters shops backing the Democratic ticket, which also include multiple union locals in battleground states like Michigan, Nevada, Pennsylvania and Wisconsin.

"These local Teamsters have committed to immediately begin knocking doors and engaging in other voter contact efforts across the battlegrounds," the statement read.

Harris is the first Democratic presidential candidate since 2000 to not receive the union's endorsement, which comes not from rank-and-file members but from the Teamsters executive council. Trump called the non-endorsement "a great honor," even though the Teamsters didn't endorse his campaign.

O'Brien was roundly criticized for his decision to speak at the Republican National Convention in Milwaukee, Wisconsin last July, though he argued that he was simply aiming to get his message out to as wide of an audience as possible. He was not invited to speak at the Democratic National Convention, with organizers opting instead to invite a retired Teamsters member to the lectern.