"State legal cannabis is now a $6 billion industry that employs 150,000 people and is on track to create more jobs than the manufacturing sector by 2020."

Mr. Sessions' stance is not just troubling, it is dangerous. It runs contrary to good policy and the facts.

Between 1970 and 2008, the U.S. incarceration rate rose fivefold. Relative to our population, we lock up seven times as many people as France, 11 times as many as the Netherlands and 15 times as many as Japan. Marijuana possession has accounted for a significant portion of those arrests.

According to the American Civil Liberties Union, between 2001 and 2010 there were 8.2 million marijuana related arrests in the county, nearly 90 percent of them were for possession. African Americans were nearly four times as likely to be arrested for possession than whites.

Since California became the first state to legalize medical marijuana two decades ago, 28 others and the District of Columbia have followed suit. Eight states have also legalized adult use. We now have a track record of legal, regulated marijuana in more than half of the country, and clear evidence that it is a better approach than a blanket prohibition and harsh prison sentences for those who use it or participate in its commerce.

A 2014 study from the University of Texas, Dallas using FBI's crime data showed no rise in crime rates resulting from medical marijuana legalization, and even some evidence of decreasing rates of homicide and assault.

According to the Drug Policy Alliance, Denver saw a 2.2 percent drop in violent crime rates in the year after the first legal recreational cannabis sales in Colorado, and overall property crime dropped by 8.9 percent in the same period while Washington, which legalized recreational use in 2012, saw violent crime rates drop by 10 percent from 2011 to 2014.

The history of the War on Drugs is also a history of the economic and social disparities in our country. Black and brown men are disproportionally incarcerated under our current drug laws, and because mass incarceration breaks up families and severely limits ex-convicts' employment and business opportunities, the War on Drugs has dramatically increased the poverty rate in minority communities.

It is a vicious cycle of prison and poverty that continues to trap millions of Americans. By one estimate, if California emptied its prisons today and sent every incarcerated person to a university it would save the state almost $7 billion a year.

It is not surprising then that prison guard unions and the private prison industry are two of the strongest opponents of marijuana legalization, along with pharmaceutical companies that see cannabis as a threat to their monopoly on prescription painkillers and other high priced treatments.

To be sure, the War on Drugs is a much bigger and more complex issue than marijuana legalization alone, but it is a good place to start. State legal cannabis is now a $6 billion industry that employs 150,000 people and is on track to create more jobs than the manufacturing sector by 2020.

It has generated hundreds of millions of dollars in tax revenue; California alone is forecasting $1 billion annually. Two decades of state legal marijuana also has shaped public opinion, with record numbers of Americans now supporting legalization. A recent poll from Quinnipiac University shows 94 percent of U.S. voters support medical marijuana programs, and 60 percent favor full legalization.

In today's divided politics, few issues command such unanimous support. Medical marijuana is legal both in red and blue states. The first ever Congressional Cannabis Caucus, announced earlier this year, is made up of two Democrats and two Republicans. And in the cannabis industry social justice and business interests are often aligned, with advocates and entrepreneurs standing shoulder to shoulder against reactionary policies such as the ones proposed by Mr. Sessions.

If he has his way on marijuana, Mr. Sessions threatens to turn back the clock on two decades of painstakingly gained progress, bringing us back to the days of overflowing prisons, disenfranchised communities and a $50 billion black market for cannabis run by drug cartels. We must not allow that to happen.

Commentary by Gina Belafonte, an actress and social justice advocate, Chris Leavy, a former Wall Street executive and current co-chairman of MedMen, a cannabis management and investment firm based in Los Angeles and Lindy Snider, an entrepreneur and philanthropist based in Philadelphia.

For more insight from CNBC contributors, follow @CNBCopinion on Twitter.

