Donald Trump doesn’t know anything about the jobs done by American autoworkers. But that hasn’t stopped him from disrespecting those workers in the crudely ignorant ways.

Trump made that disrespect abundantly clear when he appeared Tuesday for a live interview at the Economic Club of Chicago with Bloomberg’s John Micklethwait. During the interview, the Republican nominee for president volunteered his belief that autoworkers do such simplistic labor that it could be done by children.

Trump, a real estate developer, has never evidenced any particular knowledge of American manufacturing or the demands faced by working-class Americans who are employed in rapidly-evolving and highly-technical industries. But his ignorance, as the Bloomberg interview revealed, is even greater than his critics feared. Trump suggested that assembly-plant workers “take [pieces] out of a box and they assemble them. We could have a child do it.” 

That line may not have gotten a lot of notice from media outlets that provide cursory coverage of industrial and labor issues. But it was definitely heard by autoworkers like Dawnya Ferdinandsen in Toledo, Ohio. Ferdinandsen is a member of United Auto Workers Local 14, which represents workers at the 2.8-million-square-foot General Motors Toledo Propulsion Systems plant. Workers there assemble transmissions that are used in Chevrolet, Cadillac, GMC, and Buick cars and trucks.

In a video posted on social media platforms, Ferdinandsen responded to Trump’s comments, by announcing, “I challenge you, Trump, to one full 12-hour day in any auto assembly plant. I want to see you assemble parts out of a box for 12 hours. Until you accept and complete this challenge, until you actually work a manual labor job, you keep the name of the UAW out of your mouth. Solidarity, y’all.”

Shared by the UAW on Wednesday afternoon, the video was viewed more than 60,000 times in 24 hours. Another UAW video featured Elija’blu Lampkin, a member of UAW Local 1264 who works at the massive Sterling Stamping Plant in Sterling Heights, Michigan. Lampkin said, “Donald Trump has no idea what he’s doing. He does not support autoworkers. He wants to divide autoworkers, as well as this country. He couldn’t survive a day in our facility. He cannot make our company great—let alone America great again.”

Then, echoing the slogan emblazoned across the enormously popular t-shirts distributed by the union, Lampkin declared, “Donald Trump is a scab.”

Trump’s statement came in the closing weeks of an election campaign that will likely be decided by the “blue wall” battleground states of Michigan, Wisconsin, and Pennsylvania, which historically have been UAW strongholds. The union has been working for months to communicate to workers in those states that Trump is not their friend.

“Trump’s a con artist. That’s what he’s always been,” UAW President Shawn Fain explained to me last week, before Trump did the Bloomberg interview. “Unfortunately, Trump knows how to say things people want to hear.” To counter the lies, Fain said, the union has focused on the Republican’s record. “The proof of Trump is already in the body of work. Trump was president for four years. Auto plants were closing. He didn’t do a damn thing to stop any of it, to save any of it. He didn’t even make an effort to curtail any of that. He continues to tell this lie that’s he’s fixing this and he fixed that. He says he’s saving auto jobs and he’s saving working-class jobs. But his body of work, when he was president, shows different. He didn’t [fix things]. We lost jobs under Trump, and nothing improved with trade.”

That’s all true.

Now, the union has something more than Trump’s record to share with working-class voters in battleground states. The UAW has the former president’s own words from the current campaign. Those words confirm the full extent of the threat Trump’s candidacy poses to autoworkers in particular, and manufacturing workers in general.

“Every time Donald Trump gets a chance, he trashes our union and he trashes the working class,” Fain said this week. “He comes to Michigan. He talks about [how] he’s going to bring back the auto industry. Let me tell you something: Donald Trump doesn’t know shit about the auto industry.”