The Obama administration is urging the Supreme Court not to hear a case brought by two states against Colorado’s recreational marijuana law. The lawsuit threatens to end voter-approved retail sales of the drug, but legal experts aren’t convinced justices will even hear the case.

The Supreme Court has original jurisdiction over disputes between states, meaning those cases side-step the ordinary trial and appeal processes. The court is not required to hear every dispute, and Solicitor General Donald Verrilli asked the court not to accept the anti-legalization lawsuit.

Most original jurisdiction cases heard by the court deal with boundary or water disputes between states, and Verrilli argued the case filed last year by Oklahoma and Nebraska “would represent a substantial and unwarranted expansion of [the Supreme Court’s] original jurisdiction.”

The core of his argument is that Colorado is not inflicting a direct injury on neighboring states by allowing the sale and use of marijuana within state lines, and that court precedent therefore forces the matter off the table.

“At most, they have alleged that third-party lawbreakers are inflicting those injuries, and that Colorado’s legal regime makes it easier for them to do so,” Verrilli wrote. “But that is a far less direct connection between state action and the alleged injury than even the connections that this Court found insufficient in Louisiana v. Texas and Pennsylvania v. New Jersey.”

If the challenge were accepted, the Justice Department filing warned, “States could challenge any number of laws enacted by neighboring states — for example, licensing laws for firearms that are unlawful in the plaintiff states — on the theory that the laws make it more likely that third parties will enter the plaintiff states’ territory and violate their more restrictive regimes.”

States also have no obvious grounds to force strict implementation of the Controlled Substances Act, under which almost all possession of marijuana remains a federal crime, Verrilli wrote.

The Obama administration, citing prosecutorial discretion, has allowed Colorado and three other states to set up regulated recreational marijuana markets. Many other states have since the 1990s set up regulated markets for medical marijuana. Oklahoma and Nebraska are not challenging Colorado’s right to allow medical pot, possession of which is equally illegal under federal law.

Experts involved in past original jurisdiction cases at the Supreme Court say if justices do accept the lawsuit, it’s unlikely to be resolved for at least three years -- a lengthy period of time in drug reform years, as a half-dozen states may legalize recreational pot next year and as federal lawmakers warm to reform, with nearly half of the House of Representatives voting this year to protect state recreational marijuana laws from federal interference.

Special masters are appointed in all modern Supreme Court original jurisdiction cases to perform work similar to what would be done at a district court level in an ordinary lawsuit. The masters, selected through a decision-making process unclear to many of them, establish a factual record and make recommendations that justices then review.

An original jurisdiction lawsuit with the Supreme Court is “usually not as efficient as bringing a lawsuit in district court,” says Paul Verkuil, one of a handful of living attorneys who has served as a special master on an original jurisdiction case.

In addition to the interstate lawsuit, ordinary federal lawsuits against Colorado’s regulation of marijuana have been filed with Denver's federal court by upset law enforcement officials and an anti-drug group. The best-case scenario for lawsuits against Colorado’s marijuana laws likely is an end to the state's regulated market, but not a recriminalization of small-time possession or home growing.

Verkuil, a former president of the College of William and Mary who now works as a senior fellow at the Center for American Progress, served as special master in a dispute between New Jersey and New York about jurisdiction over Ellis Island, probably the highest profile original jurisdiction case recently heard. Justices awarded most of the island to New Jersey in 1998.

University of California at Irvine School of Law dean Erwin Chemerinsky, who has argued several cases before the Supreme Court, says he’s not sure if justices will hear the case.

“I thought the Solicitor General made a very compelling case against the court taking the case,” he says. “If they take it, I think it will because it presents novel issues unlike those resolved in other original jurisdiction cases."

Though the Obama administration has allowed state and tribal governments to regulate recreational marijuana sales, a future administration hostile to legalization could take legal action to force the markets offline. Most 2016 presidential candidates, however, support local autonomy.