The lawyer charged with defending Colorado's marijuana legalization laws denounced them Monday.

“It’s not worth it,” Colorado Attorney General Cynthia Coffman told dozens of fellow state attorneys general at a conference in the nation's capital, ​referring to $76 million in taxes and fees collected from pot sales last year.

The recently inaugurated Republican rebuked legalization advocates’ long-standing argument that regulating sales will eliminate the black market for marijuana and associated criminal activity.

“Don’t buy that argument,” she told her peers. “The criminals are still selling on the black market. ... We have plenty of cartel activity in Colorado [and] plenty of illegal activity that has not decreased at all.”

Coffman added that some purportedly above-board marijuana growers have exceeded allowable limits and sell marijuana in somewhat of a gray market.

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Coffman’s office is responsible for fighting a growing number of lawsuits challenging pot legalization in Colorado. Residents voted for legalization by a 10-point margin in 2012 and polls show the policy retains majority support. The state's first recreational pot stores opened in January 2014.

Though the Department of Justice has allowed state and tribal governments​ to experiment with regulated sales of marijuana, possession of the drug for any reason outside limited research is a federal crime, putting the new markets on shaky legal footing.

Sensing vulnerability, the attorneys general of Nebraska and Oklahoma in December filed a lawsuit with the Supreme Court seeking to kill Colorado’s legalization law. This month, two more lawsuits were filed by Coloradans affiliated with the anti-pot group Safe Streets.

Coffman tells U.S. News that although she personally opposes marijuana legalization, she’s not glad her office is being taken to court by people seeking to kill the reform.

“I’m never glad to be sued,” she says. “I wish there was another way to sort it out.”

Coffman's remarks echo words of caution from Colorado's Democratic governor, former brewer John Hickenlooper, who often questions the wisdom of legalizing marijuana and urges restraint on other states.

Mason Tvert, the Colorado-based communications director of the Marijuana Policy Project, tells U.S. News Coffman’s views on marijuana aren't well-known, and he hopes she will vigorously defend legalization in court.

Tvert adds that Coffman’s remarks about black market sales are counter-intuitive.

“If hundreds of millions of dollars in marijuana sales are taking place in licensed businesses, where would they be taking place if they were illegal?” he says. "It's hard to imagine how anyone, let alone our state's top law enforcement official, could fail to recognize the impact our laws are having on the underground market."

About $700 million in marijuana was sold legally in Colorado last year.

Before Coffman's remarks at the Monday summit, her Nebraska counterpart, Republican Doug Peterson, distanced himself from the lawsuit challenging Colorado’s law, initiated by his predecessor Jon Bruning and Oklahoma Attorney General Scott Pruitt, both also Republicans.

“It wasn’t my idea,” Peterson said.

Pruitt didn’t check in to the event, put on by the National Association of Attorneys General, on Monday afternoon.

Marijuana was on the minds of many of the officials present.

Iowa's attorney general, Democrat Tom Miller, said he believes states should be allowed to act as laboratories of democracy. Hawaii's new attorney general, Democrat Doug Chin, sought guidance from colleagues on medical pot regulations.

North Dakota Attorney General Wayne Stenehjem, a Republican, tells U.S. News he first learned Monday about the Nebraska and Oklahoma lawsuit against Colorado, and that he had not made any decision about whether he'd like to join the suit.

Meanwhile, it appears Washington state's marijuana legalization law is safe from its neighbors. The attorney general of Idaho, Lawrence Wasden, tells U.S. News he will not be suing Washington.

“I don’t see a cause of action against Washington," Wasden says. Both Idaho and Washington are sovereign states and have a right to make their own laws, he said.

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With a broad smile that betrayed his feelings, Wasden declined to comment on other states' lawsuit against Colorado.