Senator Vance’s decision to cross the so-called digital picket line to write an opinion piece for the Pittsburgh Post-Gazette on Thursday is drawing denunciations from union leaders and the paper’s employees more than two years after the strike began.

Mr. Vance took to the pages of the Post-Gazette to make the case that Catholics should support President Trump this year. 

Mr. Vance’s opinion piece — titled “Kamala Harris’ prejudice against Catholics” — was published on Thursday. In it, he argues that Ms. Harris’ record is an “antagonistic” one toward Catholics, citing her denunciation of the Supreme Court’s decision in the case of a Colorado baker who declined to make a cake for a gay wedding because of his religious beliefs, as well as her support for the Equality Act, which the Conference of Catholic Bishops describes as an assault on religious liberties. 

The motivation for doing such an opinion piece less than two weeks before election day is likely meant to spur Catholic voters to get to the polls. At Alleghany County, which is home to Pittsburgh, the total number of practicing Catholics is more than 450,000. 

Union leaders were quick to call Mr. Vance out for his betrayal. The president of the NewsGuild–Communication Workers of America union, Jon Schleuss, said that Mr. Vance “is a scab just like anybody else who crosses a picket line.”

Several union groups took to X on Thursday to similarly denounce Mr. Vance’s decision to pen the opinion piece amid the strike, which began in October 2022. 

“This is an outrageous attack on our strikers; they need our support more than ever,” the NewsGuild–CWA union said in a post online. “Stand against scabs like JD Vance and the union-busting bosses at the Post-Gazette by donating to support strikers here,” they wrote, including a link to donate to their strike fund. 

A Pittsburgh area native and colleague of Mr. Vance, Senator Fetterman, also weighed in on the controversy on Thursday. “For 2 years, @ThePUPNews workers have been striking for dignified working conditions and benefits,” Mr. Fetterman wrote on X, tagging the account being used by Post-Gazette employees to advocate for themselves. “The union way of life is just a talking point to scabs like Silicon Valley Vance.”

The president of the American Federation of Labor and Congress of Industrial Organizations, Liz Shuler, called Mr. Vance “a piece of work” after the opinion piece was published. The United Auto Workers criticized Mr. Vance in another X post, saying he was not living up to his promise to be part of “the most pro-worker Republican ticket in history.” 

“JD VANCE IS A SCAB,” the UAW wrote on a graphic that they shared on X. 

“Don’t go into work for the Pittsburgh Post-Gazette. Don’t click on the Pittsburgh Post-Gazette. Don’t share articles from the Pittsburgh Post-Gazette,” the CWA wrote in their own X post. 

“Full support (as always) to our siblings in Pittsburgh. If you cross a picket line, you are a scab. It’s that simple,” the New York chapter of the News Guild union says. 

The Trump campaign did not immediately respond to a request for comment. 

Mr. Vance’s populist bona fides were part of the reason that Trump selected him as his running mate in the first place, arguing that a hardscrabble kid from Ohio would be a fighter for the MAGA movement and Americans of all income levels. At the Republican National Convention in July, Speaker McCarthy told the Sun that Mr. Vance’s policy prescriptions would help the Trump campaign win over even more blue collar voters in midwestern states.