These Nine States Will Vote on Legalizing Recreational and Medical Marijuana - NBCNews.com

Nine states have marijuana measures on the ballot this November, and chances are good that many will pass — giving pot advocates high hopes that the federal government will eventually lift its nationwide ban.

In five states — Arizona, California, Maine, Massachusetts and Nevada — voters will decide on legalizing the recreational use of marijuana.

In four others — Arkansas, Florida, Montana and North Dakota — voters will weigh in on medical marijuana, which is already legal in nearly half the country.

As Election Day approaches, polls and research show rising support for marijuana legalization: 57 percent of U.S. adults say marijuana should be made legal, compared to just 32 percent a decade ago, found a Pew study earlier this week.

Supporters say the shift in attitude is in part thanks to successes in Colorado and Washington, the first states where voters approved recreational marijuana in 2014.

"There's nothing more powerful when you're trying to affect social change than having examples out there that are actually working," Keith Stroup, founder and legal counsel at the nonprofit National Organization for the Reform of Marijuana Laws (NORML), told NBC News.

Detractors' fears about the dangers of legalizing pot "simply haven't materialized," he added. "They can't really make those arguments effectively today because we have more than two years of a track record in Colorado and Washington."