Donald Trump’s proposal to stop Muslims from entering the U.S. continues to stir controversy. The Republican front-runner called for a complete ban on admitting Muslims until government officials can figure out what is going on when it comes to extremism and terrorism.

Among those who are critical of the idea is Kansas Governor Sam Brownback. The governor tells KSAL News “I don’t agree with it, I stand for religious freedom.”

Brownback says that he thinks it is not appropriate to ban people because of their religion. He also says that he believes that it would not withstand a constitutional challenge.

The governor adds, though, that he thinks that we need to be more careful, and cautious, with countries where we have seen radicalized elements come out of. We need to be vigilant of people traveling in and out of those regions. “We did that after 911,” he said.

Trump’s proposal has been condemned by many Republican candidates, but cheered by many Trump supporters.