3 states to vote on recreational pot use

Is the United States on the verge of legalizing pot? Already 17 states and the District of Columbia allow the medical use of marijuana, and on Nov. 6, voters in three states will decide whether adults should be able to buy it for recreational use.

Ballot measures in Washington, Oregon and Colorado are in direct conflict with federal law, an issue that opponents hope will sway voters. But the measures are polling well in Washington and Colorado and getting support across the political spectrum, including from some high-profile conservative Republicans, The Washington Post reports.

The issue is in play on a national level, too. In Colorado alone, campaigns for and against the state's Amendment 64 have reportedly spent well over $3 million, much of it from out-of-state organizations on both sides. "This is a big deal, and I think the federal government knows that," said Sam Kamin, a law professor at the University of Denver. "And I think they're watching these elections very closely."

Supporters of legalized marijuana have also been more politically savvy in this round of elections, compared with during earlier efforts, such as a failed 2010 attempt in California. They are pointing to the hundreds of thousands, perhaps millions, of dollars that strictly regulated marijuana sales programs could bring to state coffers.

But Kamin, who has been closely watching the battle over Colorado's Amendment 64, believes those numbers are optimistic. "The extent to which this will become a large-scale industry really depends on federal acquiescence," he said. "If the feds come in and shut everyone down, it's not going to be a big boon for the cities and for the state government. (But) if it happens and this rivals tourism in attracting people to our state, this might provide some financial benefits."

Kamin and other observers also note a generational gap when it comes to the legalization issue, akin to how voters approach gay marriage. For younger voters, he says, "medical marijuana, legalization of marijuana is not something they're very troubled by. They're usually very pro. Similarly, gay marriage is not something that bothers them. It's only when you go up in years that you see strong opposition to it."

So is the tide turning? A Gallup poll taken last year said half of Americans surveyed favored the legalization of marijuana use, up from 46% in the previous year. And a recent Seattle Times editorial endorsed the state's Initiative 502, saying that, rather than continued criminalization of marijuana use, "the better policy is to legalize it, license it, regulate it and tax it."

But Kamin believes that, should these measures pass in any of the three states, it will only signal the beginning of the real battle over legalization.

"If it does pass somewhere, that does not mean that all of its provisions will go into effect right away," he says. "We may see a federal crackdown. We may see court challenges. It's sort of the start and not the end of what happens."

More from MSN Money

• Why gun sales are booming
• The 19 richest members of Congress
• $370 million for pet costumes?