Marijuana plants grow in a greenhouse at the Los Suenos Farms facility in Avondale, Colo., on Feb. 25. (Matthew Staver/Bloomberg News)

The Supreme Court on Monday declined to take up a complaint from neighboring states that Colorado’s relaxation of marijuana laws hurts them and undermines federal law.

The court without comment turned down the petition from Nebraska and Oklahoma.

Those states said that Colorado’s move to decriminalize certain uses of marijuana increased trafficking into their states, requiring them to expend significant “law enforcement, judicial system and penal system resources.”

“The State of Colorado authorizes, oversees, protects, and profits from a sprawling ­$100-million per-month marijuana growing, processing, and retailing organization that exported thousands of pounds of marijuana to some 36 states in 2014,” the states said in their petition to the court.

“If this entity were based south of our border, the federal government would prosecute it as a drug cartel.”

Colorado voters in 2012 decriminalized the possession of one ounce of marijuana by residents of the state 21 or older. Colorado does not allow transporting pot out of the state.

The Obama administration said the change and the loosening of penalties in other states did not undermine federal drug laws and advised the court not to accept the case.

Solicitor General Donald B. Verrilli Jr. said Nebraska and Oklahoma had not shown the kind of direct injury that warrants granting what the court calls original jurisdiction to hear interstate disagreements.

“Entertaining the type of dispute at issue here — essentially that one state’s laws make it more likely that third parties will violate federal and state law in another state — would represent a substantial and unwarranted expansion of this court’s original jurisdiction,” Verrilli said.

Justices Clarence Thomas and Samuel A. Alito Jr. dissented from the decision not to take the case, saying the court had an obligation to settle such disputes between states.

“The plaintiffs have alleged significant harm to their sovereign interests caused by another state,” Thomas wrote. “Whatever the merits of the plaintiff state’s claims, we should let this complaint proceed further rather than denying leave without so much as a word of explanation.”

The court also overturned a ruling by the Massachusetts Supreme Court that upheld a state law prohibiting the possession of stun guns.

The justices in an unsigned opinion said the state court’s ruling was not consistent with its decision in District of Columbia v. Heller that said the Second Amendment provided an individual right to gun ownership.

The decision said the Second Amendment covers “all instruments that constitute bearable arms, even those that were not in existence at the time of the founding.”

The Supreme Court’s order Monday said the reasons the state court “offered for upholding the law contradicts this court’s precedent” and sent it back.

The cases are Nebraska v. Colorado and Caetano v. Massachusetts.