Montana may not enforce a law that prohibits certified nurse practitioners and nurse midwives from performing early-term abortions pending a decision on the law’s merits, a state court said.

Helen Weems and Jane Doe had standing to challenge the constitutionality of a law that says only licensed physicians and certified physician assistants may perform previability abortions, a split Montana Supreme Court said April 26.

The court rejected the state’s “circular” argument that Weems and Doe couldn’t challenge the law unless they were licensed to perform abortions, even though the law prevents them from seeking licensure to do so. The law...