The United States Supreme Court refused to hear a lawsuit launched by Oklahoma and Nebraska against Colorado over marijuana legalization on Monday.

The suit, which Oklahoma and Nebraska's attorneys general filed directly with the Supreme Court 15 months ago, alleges that Colorado's legalization of marijuana is in direct conflict with federal law and has been responsible for increased crime in both states.

The two states argued that Colorado is culpable for authorizing, protecting and profiting from a $1 billion industry dealing federally-illegal drugs.

"If this entity were based south of our border, the federal government would prosecute it as a drug cartel," one of the briefs sent to the Supreme Court said.

The justices voted 6-2 to not hear the case, but Oklahoma and Nebraska are able to file the suit in U.S. District Court.

Before handing down the decision, the justices asked the Obama administration for guidance and the Justice Department told the court not to hear the case.

"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," Solicitor General Donald Verrilli said.

As for Colorado's governor, John Hickenlooper, he said that his constituents voted to legalize marijuana and have set up a responsible industry.

"Since Colorado voters overwhelming passed legal recreational marijuana in 2012, we have worked diligently to put in place a regulatory framework--the first in the world--that allows this new industry to operate while protecting public health and safety," he said in a statement.

Across the board, the marijuana industry took a sigh of relief.

Tom Angell, chairman of Marijuana Majority, summed it up:

"There's no question about it: This is good news for legalization supporters. This case, if it went forward and the Court ruled the wrong way, had the potential to roll back many of the gains our movement has achieved to date," Angell said in an email. "And the notion of the Supreme Court standing in the way could have cast a dark shadow on the marijuana ballot measures voters will consider this November."

Cannabis legalization, which is supported by over 50 percent of the country, will likely be on the ballot in at least seven key states come election day. To date, 23 states and Washington, D.C. have some form of legalization, with full adult use legal in Alaska, Colorado, Oregon, and Washington state.

Andy Williams, a cofounder of Medicine Man, one of the largest producers and dispensaries in Colorado, applauded the justices' decision.

"The Supreme Court has protected the will of the people today and I believe the court has demonstrated that it understands legal cannabis is a fundamental right," Williams said.

This is not the first lawsuit waged after Colorado's marijuana legalization. The Holiday Inn in Frisco, Colorado, sued a marijuana dispensary under the Racketeering Influence and Corrupt Organizations Act and the pot shop closed down and settled; a Colorado horse ranch used the RICO Act to launch a suit against a cultivation facility but it was dismissed; and a group of sheriffs across Colorado, Kansas, and Nebraska had their case dismissed, too.

But what was different with this case was that the heart of Oklahoma and Nebraska's argument focused on the Supremacy Clause of the Constitution, which says federal law trumps state law. Even though marijuana is still a controlled substance and illegal under federal law, the government has allowed states to experiment with legalization. Over the last eight years, President Obama has forced the Department of Justice to withhold funding from the Drug Enforcement Agency to be use to fight medical marijuana and has urged banks to serve the industry.

The plaintiffs can still file the suit in the U.S. District Court.

"Coloradans legalized cannabis because of the terrible effects of prohibition. It's time that other states take a good look at the positive effects of legalization instead of sticking to the status quo." Kyle Sherman, CEO of Flowhub, a Denver-based startup helping growers meet compliance regulations, said via email.

As for Oklahoma and Nebraska, Angell has some advice for the states fighting against progressive drug laws.

"At the end of the day, if officials in Nebraska and Oklahoma are upset about how much time and resources their police are spending on marijuana cases, as they said in their briefs, they should join Colorado in replacing prohibition with legalization," he writes. "That will allow their criminal justice systems to focus on real crime, and it will generate revenue that can be used to pay for healthcare, education and public safety programs."