The crypto industry’s long-coveted Clarity Act has attracted plenty of opponents in recent months, among them Wall Street leaders, consumer advocates, law enforcement groups, and Native American tribes. Now, the market structure bill has attracted the ire of a new and perhaps unexpected constituency: Catholics.

In a letter sent Tuesday to Senate leaders in both parties, a coalition of Catholic leaders and organizations warned that the legislation—which would legalize most crypto activity in the United States—could violate Christian beliefs by enabling the funding of human trafficking.

“Catholic social teaching calls us to uphold solidarity, protect the vulnerable, and ensure that economic systems are ordered toward…