The federal government this week advised the Supreme Court to avoid weighing in on a lawsuit brought by Nebraska and Oklahoma over Colorado’s system of legalized recreational marijuana, according to USA Today.

Nebraska and Oklahoma, which border Colorado, say they are having trouble protecting their borders from the increased flow of marijuana, the article notes. The two states filed a lawsuit against Colorado with the U.S. Supreme Court, asking to block Colorado’s legal marijuana system. The states said Colorado’s law legalizing recreational marijuana is unconstitutional and places a burden on them.

The suit argues that because marijuana is illegal at the federal level, Colorado’s system violates federal interstate commerce laws and the Controlled Substances Act.

Colorado asked the court to throw out the case. Last spring, the Supreme Court asked for the Obama Administration’s view on the suit.

On Wednesday, Solicitor General Donald B. Verrilli filed a brief with the Supreme Court arguing that if the court took the case, it would “represent a substantial and unwarranted expansion” of the court’s original jurisdiction.

He said the Supreme Court usually avoids getting involved in disputes between states unless the states themselves are at odds. He noted Oklahoma and Nebraska have sued Colorado over the actions of private citizens who are breaking the law.

“Nebraska and Oklahoma essentially contend that Colorado’s authorization of licensed intrastate marijuana production and distribution increases the likelihood that third parties will commit criminal offenses in Nebraska and Oklahoma by bringing marijuana purchased from licensed entities in Colorado into those states,” Verrelli wrote. “But they do not allege that Colorado has directed or authorized any individual to transport marijuana into their territories in violation of their laws. Nor would any such allegation be plausible.”