Democratic congressional nominee Sean Casten once argued that President Trump and 9/11 mastermind Osama bin Laden had a “tremendous amount in common,” according to newly published audio.

A clip obtained by the Washington Free Beacon showed Mr. Casten, who is challenging Republican Rep. Peter Roskam in Illinois, talking to voters in February about how gun-control opponents are apparently similar to Islamic terrorists by how they aim to recruit “marginalized young men.”

“In many ways — and I don’t mean to sound overly, I don’t know, hyperbolic on this — Trump and Osama bin Laden have a tremendous amount in common,” Mr. Casten said, according to the audio clip. “Because they have both figured out how to use the bully pulpit to activate marginalized young men. It’s the same pool. Every demagogue has done this — find a group of angry people and give them something to be angry at.”

The Democrat made the comparison after he was asked how he planned to improve safety in schools in light of recent mass shootings.

Mr. Casten slammed the “pernicious influence of gun money in politics” and lamented that until that changed, the violence would continue.

Mr. Casten’s campaign declined to respond to the Free Beacon’s request for comment.

A spokeswoman for Mr. Roskam’s campaign, Veronica Vera, slammed Mr. Casten in a statement Thursday evening, accusing the Democratic challenger of a history of “vicious” rhetoric.

“Sean Casten has called Republicans pedophiles, likened abortion to gallbladder surgery and called Republican Party donors ‘a bunch of morons,’” she wrote. “Our communities need a solutions-oriented Representative who can bring people together to get things done. This kind of hateful, vicious language is exactly the wrong approach.”