A new poll from the Associated Press shows that American attitudes toward the legalization of personal amounts of marijuana has plummeted since Washington and Colorado did just that in 2012. A 2010 AP poll found 55 percent of adults opposed legalization while the latest poll released this week showed only 29 percent in opposition. As recently as 1990, 84 percent of adults opposed legalization.

Support for legalization in this poll hasn’t changed much -- it was 33 percent support in 2010 and just 36 percent support now. The big shift was in people who were neutral on legalization, which jumped from 11 percent in 2010 to 33 percent now. With a full third of these voters on the fence it shows the need for the argument not just that prohibition is bad, but that legalization is good.

How these questions are asked can make a big difference in the results. The 2010 poll was conducted by telephone and the 2013 poll was conducted online. Experts say respondents are more likely to indicate a “neutral” response online as they don’t feel pressure to have an opinion like they do when speaking to another person. However, taken with the recent Pew Research and Gallup polls that have both increased from 47 and 48 percent, respectively, to 52 and 58 percent after two states legalized marijuana, it seems clear that Americans are ready to end marijuana prohibition.

Additionally, Americans are beginning to hear us on the potential outcomes of marijuana legalization. An increasing number, now over a third of Americans (37%) believe legalization will help the economy. A decreasing number, now under a third of Americans (32%) believe marijuana is the gateway drug that will lead to harder drug abuse and an increasing number (17%) believe it helps people get off harder drugs. And legality will make a difference in whether people use marijuana, with 19 percent saying they will use it post-legalization, compared to the 12 percent in the National Survey on Drug Use & Health who admit using at least once in the past year.

Throughout this year’s polls, one can find variances in support depending on whether the poll asks about “legalizing possession” versus “legalizing use” or “tax and regulate” versus “treat it like alcohol,” but the trends are all the same: Americans increasingly believe prohibiting marijuana is a failed policy and some form of legal regulation needs to be established.

"Radical" Russ Belville is the host of "The Russ Belville Show."