Oklahoma Attorney General Scott Pruitt, a vocal proponent of states’ rights, drew criticism Monday from fellow Republicans who oppose his attempt to have the U.S. Supreme Court overturn Colorado’s marijuana legalization law.

State Rep. Mike Ritze, R-Broken Arrow, and six other GOP lawmakers sent a letter to Pruitt criticizing his decision to join Nebraska in asking the high court to invalidate Colorado voters’ 2012 determination to legalize marijuana for recreational use.

They want him to remove Oklahoma from that legal fight, saying he should not meddle in the affairs of another state.

“This is not about marijuana at its core — it is about the U.S. Constitution, the 10th Amendment, and the right of states to govern themselves as they see fit,” Ritze said. “If the Supreme Court can force Colorado to criminalize a substance or activity and commandeer state resources to enforce extra-constitutional federal statutes and U.N. agreements, then it can essentially do anything, and states become mere administrative units for Washington, D.C.