Partisan hecklers were out in force in Boston at the International Association of Fire Fighters.

Angry delegates peppered JD Vance’s address at their International Convention Thursday with jeers and boos — a stark difference from the previous day’s stop from his Democratic counterpart.

Vance faced the crowd with determination, saying: “It sounds like we’ve got some fans and some haters. That’s okay.”

It’s fair to say his audience was not entirely receptive to his message.

“Today, I’m asking you to ignore the campaign rhetoric and to look at the records. In 2019, this union endorsed a Democrat for president with high hopes. But sadly, I believe that you have been let down,” Vance said.

Before Minnesota Gov. Tim Walz visited the gathering on Wednesday, there were lines wrapped partway around the exterior of the massive Boston Convention and Exhibition Center in both directions.

Ahead of Vance’s arrival, the lines were non-existent. Walking through security took as long as taking a jacket off.

When Walz took to the stage and told the union representing 350,000 firefighters, paramedics, and support staff about his and Vice President Kamala Harris’s pro-worker background, he brought the crowd to their feet several times.

Vance’s appearance before the convention on its last day was not announced in advance by the Trump campaign. Reporters on-site shared they’d only learned of his appearance through union communications staff and via rumors shared by delegates.

Maybe someone knew how things would go.

“Scab!” an audience member yelled to the sitting U.S. senator from Ohio — and U.S. Marine veteran — as he walked away about 20 minutes after he started speaking.

Aside from mostly sporadic clapping from audience members, Vance didn’t receive much response to questions. If his address included a joke or amusing anecdote, the crowd’s overall stoicism showed that it didn’t land.

Case in point: Vance told what could have been a heartwarming story about firefighters at stations he visited being kind to his three children.

Another: “Are you administering more Narcan than you did four years ago?” he asked. Silence.

Under Trump, Vance claimed, “wages were rising, and nobody was really talking about inflation in 2020,” despite the fact that through much of 2020, the nation was in the midst of a crippling pandemic and that potential government intervention had future inflation very much on people’s minds.

Trump, Vance said, secured the border.

People are dying of drug overdoses too often under the Biden-Harris administration, Vance said, without adding deaths have been rising for 20 years.

When Trump is reelected as president, “we won’t sit on our hands while rioters and arsonists burn down American cities,” Vance said, citing the riots that occurred in the summer of 2020 following the murder of George Floyd as evidence of government inaction in the face of violence.

Vance tried to assure the audience of first responders that though in private they “fear they are not making a difference,” they are in fact helping their communities.

The audience seemed to have all they could take when Vance said “President Trump and I are proud to be the most pro-worker Republican ticket in history.”

“Liar!” someone with a thick Boston accent shouted over the boos.

Republican candidate for Vice President JD Vance speaks at the International Association Of Firefighters convention Thursday. (Nancy Lane/Boston Herald)