Why did the Supreme Court deny a challenge to Colorado's pot laws?

A bid by the states of Nebraska and Oklahoma to have Colorado’s recreational marijuana laws declared unconstitutional stalled Monday, when the Supreme Court declined to hear the legal challenge brought by Colorado’s neighbors.

The 6-to-2 decision means the court won't hear Nebraska and Oklahoma’s complaint, but the states could still bring the matter to lower courts.

Justices Clarence Thomas and Samuel Alito were the lone dissenters in the ruling, writing that the Court “should let this complaint proceed further.” A majority opinion was not released.

Before deciding whether to accept Nebraska and Oklahoma’s filing, the Supreme Court asked US Solicitor General Donald Verrilli, Jr. to examine the suit and recommend a course of action. In an opinion released in December, Mr. Verrilli concurred with Colorado’s reasoning, saying that taking on the case as proposed “would represent a substantial and unwarranted expansion of this Court’s original jurisdiction,” and that Nebraska and Oklahoma’s complaint should be denied.

Original jurisdiction refers to the right of a court to hear a case first, rather than through appellate jurisdiction in which a high court rules on lower courts' decisions. Original jurisdiction has been invoked sparingly in the US judicial system, usually to settle interstate territorial or resource disputes.

In January, Nebraska and Oklahoma filed a supplemental brief to their 2014 lawsuit with the high court in which they responded to Mr. Verrilli’s assessment and argued that the “sprawling $100-million-per-month marijuana growing, processing, and retailing organization” authorized by Colorado voters in 2012 conflicts with the Controlled Substances Act (CSA), and that the Colorado marijuana industry was causing harm in its neighboring states.

The states’ lawyers brief argued that “Colorado’s actions have directly caused Nebraska’s and Oklahoma’s harms,” and that the Centennial State should be held responsible for the damage its marijuana inflicts on its neighbors in the same way that bartenders would be “held responsible for the drunk who kills a family with his car” after knowingly selling the drunk “ten beers in two hours.”

In Colorado’s response to its neighbors’ original lawsuit, the state acknowledged the $700-million marijuana industry (half of it in medical marijuana) but said that Nebraska and Oklahoma’s methods of challenging the trade were a “dangerous use” of the Supreme Court’s original jurisdiction and of the Supremacy Clause that establishes state laws as subordinate to the US Constitution and federal laws.

While recreational marijuana use and sale remains illegal federally, the Department of Justice had stated that while interstate marijuana trafficking would remain an investigative priority, the department would effectively defer to states with legalized marijuana to regulate the drug. 

The Colorado response went on to argue that the state’s marijuana regulatory system does not violate other states’ sovereign rights, a qualification for the invocation of original jurisdiction, and that the subject of the suit would have been better suited for debate in lower courts and a traditional appeals process.

Colorado remains one of four US states where the recreational marijuana trade is legal, joined by Oregon, Washington state, and Alaska. Voters in the District of Columbia legalized the possession and use of marijuana, but Congress intervened to block its sale and taxation in the federal district.

At least 10 states are considering some form of legalization of marijuana in 2016, reports International Business Times.