CEDAR RAPIDS, Iowa—GOP presidential candidate Gov. Scott Walker says he supports the First Amendment Defense Act, a bill that would prevent the federal government from taking action against individuals or businesses because of their religiously held beliefs on traditional marriage.

“Absolutely. To me, protecting our constitutional rights shouldn’t just take a piece of legislation,” Walker said during an interview with The Daily Signal aboard his campaign bus in Iowa. “That’s something the president and elected members of the House and Senate by the oath we take, I take an oath as a governor to not only support the Constitution, not only of my state but the United States. I think that’s implicit. The oath that any federal officer takes is about upholding the Constitution. The Constitution is very clear about protecting those rights.”

The religious liberty bill was introduced in the Senate by Mike Lee, R-Utah, and in the House by Raúl Labrador, R-Idaho, about a week before the Supreme Court ruled in favor of same-sex marriage. Walker called that ruling a “grave mistake” and is pushing a constitutional amendment that would allow states to define the marriage issue, not the courts.