If you are a presidential candidate, you spend a lot of time talking to people in Iowa. And if you’re a Republican, that means a lot of time on Iowa conservative radio, including popular programs hosted by right-wing activists Steve Deace and Jan Mickelson.

The fact that Deace and Mickelson have long histories of extreme rhetoric has not dissuaded Republican candidates from joining their shows. But Mickelson just upped the ante with comments he made on his program today.

Media Matters caught Mickelson proposing that undocumented immigrants in Iowa become “property of the state” and pressed into hard labor. When a listener called in to point out that Mickelson’s proposal “sounds like slavery,” Mickelson asked, “Well, what’s wrong with slavery?” Undocumented immigrants, he went on to say, are the ones who are enslaving American citizens:

It will be interesting to see if any of the GOP candidates who have been on Mickelson’s radio program recently — which, according to Media Matters’ count, includes Rand Paul, Mike Huckabee, Ted Cruz, Lindsey Graham, Ben Carson, Carly Fiorina, Marco Rubio, Scott Walker, Rick Santorum and Bobby Jindal — repudiate his remarks.

But the fact is that if these candidates were concerned about Mickelson’s rhetoric, they should have stopped going on his show long ago.

When Graham appeared on his program in June, Mickelson declared his allegiance to the Confederacy, as Graham scrambled to distance himself:

Mickelson has also backed Jim Crow-type voting laws.

Today’s comments are hardly Mickelson’s first foray into anti-immigrant extremism either. He has proposed barring undocumented children from public schools and said that if someone has a Hispanic name and is involved with the police, “I assume you’re not here legally.” After an interview with anti-immigrant activist Ann Corcoran, Mickelson promised to press every candidate he had on his show to oppose the U.S. resettlement of refugees from war-torn Muslim countries, which he said was an “act of jihad.” When he asked Rand Paul about it, Paul said the U.S. shouldn’t resettle Iraqi refugees because “we won the war.”

Mickelson’s anti-gay activism includes calling AIDS an “invention” of God to punish homosexuality and agreeing with former Iranian President Mahmoud Ahmedinejad on the issue of homosexuality.

The Iowa talk radio host also enjoys promoting fringe right-wing conspiracy theories. Mickelson helped to bring the Jade Helm 15 conspiracy theory into the GOP mainstream, asking Paul on his program about the supposed federal plan to take over Texas .

And just last week, Mickelson was getting Rep. Steve King to entertain the conspiracy theory that a botched EPA mine cleanup in Colorado was a deliberate plan to pollute a river to create a Superfund site:

Republican candidates may try to avoid Mickelson’s show after today. But given their track record, we somehow doubt that they will.