InterVarsity Christian Fellowship (IVCF) is suing the University of Iowa after the school kicked the group—along with 37 others—off campus.

According to Becket, which is representing IVCF, the group has been part of campus life for 25 years, but because IVCF asks its leaders to embrace the group’s mission, the school in June ordered the group to drop that requirement within two weeks or be deregistered. It said IVCF could not even “strongly encourage” its leaders to embrace its faith. When IVCF explained that it could not eliminate its standards, the school deregistered it, along with dozens of other religious, cultural and ideological student groups.

“If public universities really want to foster an intellectually diverse environment, this isn’t how to do it,” said Daniel Blomberg, senior counsel at Becket. “Banning religious groups from having religious leaders just flattens diversity and impoverishes the campus.”

The university has temporarily reinstated the groups pending the outcome of the lawsuit.