WASHINGTON—The Supreme Court on Monday rejected an effort to void Colorado’s legalization of marijuana, declining to hear Nebraska and Oklahoma’s claim that the 2012 voter initiative harmed them by increasing drug trafficking across their borders.

The court has the power to hear disputes between states, which typically involve boundary questions or water rights. The Nebraska-Oklahoma lawsuit was a far more ambitious claim—that one state’s power over its own criminal laws was limited by their alleged impact on other states.

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