"Semper Fi, guys," Vance said in response to the boos, using the motto of the U.S. Marine Corps, in which he served. "Sounds like we got some fans and some haters. That's okay; let's listen to what I have to say here, and I'll make my pitch."
That pitch to the IAFF—which has yet to endorse a presidential candidate—included the claim that "President Trump and I are proud to be the most pro-worker Republican ticket in history, and I want to talk about why we are fighting for working people, why we are going to fight for unions and nonunions alike."
This drew another salvo of boos.
A pro-Democrat account with more than 680,000 followers on X, the social media platform formerly known as Twitter, mocked Vance's IAFF reception in a post saying that "Donald Trump and JD Vance are scabs and the audience knows it."
Vance did receive applause after saying that he respects the IAFF for "inviting both sides to take the stage" during the union's convention.
Walz—who is Vice President Kamala Harris' Democratic running mate—touted his party's strong union ties, as well as his own status as a "card-carrying member of Minnesota's teachers union," during his IAFF convention speech on Wednesday. He said that a Harris-Walz administration would support legislation including the Richard L. Trumka Protecting the Right to Organize (PRO) Act, which if passed would expand labor protections including the right to organize and collectively bargain.
"We know that when unions are strong, America's strong," Walz said to robust applause.
Union leaders have warned that a Trump-Vance administration would be inimical to organized labor, with AFL-CIO president Liz Shuler calling the GOP ticket "a corporate CEO's dream" and American Federation of Teachers chief Randi Weingarten hailing the administration of Democratic President Joe Biden as "the most pro-labor, pro-public education leaders our country has seen in modern history."
Last month, United Auto Workers—one of many unions endorsing Harris—called Trump "a scab and a billionaire."
"We know which side we're on," the union added. "Not his."