American views on marijuana have shifted incredibly rapidly. Thirty years ago, marijuana legalization seemed like a lost cause. In 1988, only 24 percent of Americans supported legalization.

But steadily, the nation began to liberalize. By 2018, 66 percent of U.S. residents offered their approval, transforming marijuana legalization from a libertarian fantasy into a mainstream cause. Many state laws have changed as well. Over the last quarter-century, 10 states have legalized recreational marijuana, while 22 states have legalized medical marijuana.

So why has public opinion changed dramatically in favor of legalization? In a study published this February, we examined a range of possible reasons, finding that the media likely had the greatest influence.

It’s not about use, geography or demographics

Our study ruled out a few obvious possibilities.

For one, it’s not about marijuana use. Yes, marijuana use has increased. Data from the National Survey on Drug Use and Health show that, in 2002, about 10 percent of adults reported using marijuana the previous year. By 2015, 13.5 percent reported using. But that increase is too small to have had much of an impact on attitudes. [Read more at PBS]