It’s usually a friend to the GOP, having endorsed Donald Trump for president in 2016, but the Fraternal Order of Police, the nation’s largest law-enforcement labor union, has come out swinging at Republican U.S. Sen. Cory Gardner. What’s the beef? Gardner’s vow to hold up nominees to the many vacant posts in the U.S. Justice Department after the Trump administration announced it was giving the department more leeway to crack down on pot-legalizing states like Colorado.

In a press statement released Friday, police union President Chuck Canterbury said the union’s rank and file “are disappointed and very frustrated” by Gardner’s vow:

“…(T)he fact that he believes Colorado can profit from the sale of this illegal drug does not give him the right to hold up or delay the appointment of critical personnel at the Justice Department. … Senator Gardner does a real disservice to the nation as a whole, and we urgently ask him to reconsider his rash and ill-advised obstructionism.”

In a parting shot, Canterbury added:

“The ability of the Justice Department to carry out its nationwide mission should not be compromised by a single senator trying to make it easier for business in his state to sell marijuana – an illegal drug as far as the federal government is concerned.”

The clash is ironic. Gardner personally had opposed the statewide ballot issue legalizing marijuana. Now, he’s staring down law-and-order types with whom he actually agrees on that core issue – in defense of another conservative tenet: states’ rights.