The Federal government (including the U.S. Supreme Court) has no jurisdiction in state marriage laws. In 1896 it no jurisdiction, either. The Supreme Court ruling from 1896 was based on the legal argument that the U.S. law requiring Utah to outlaw polygamy as a condition of statehood was valid on constitutional grounds because Utah was a Federal territory (not a state) at the time the law was passed.
The Utah legislature could have passed a state marriage law allowing polygamy and told the U.S. Supreme Court to "#*%& off!" immediately after statehood had been granted, but they didn't. It took 117 years, but it looks like someone finally did.
Except the Constitution of the State of Utah outlaws polygamy and says that the polygamy prohibition cannot be changed without the consent of the federal government.