Medical marijuana user Ezekiel Muses checks out a jar of medical marijuana, that he uses for back pain, at the CANNA CARE medical marijuana dispensory, in Sacramento, Calif., Tuesday, Sept. 21, 2010. (AP Photo/Rich Pedroncelli)

Millions of Americans are heading to the polls this Election Day, but the vote for president is not the only thing on the ballot.

In an unprecedented move, three states will vote on whether to allow the recreational use of marijuana.

Voters in Colorado, Oregon and Washington are all considering measures that would effectively legalize pot in their respective states.

If the measures are approved residents over 21 would be permitted to possess cannabis, much like cigarettes or alcohol, from stores licensed and regulated by the state.

“After 75 years the prohibition has failed and people have access to marijuana as readily as alcohol, tobacco and caffeine,” said Allen St. Pierre, executive director of the Washington DC-based, National Organization for the Reform of Marijuana Laws (NORML). “Unlike those three drugs cannabis is not regulated or taxed. Now, 50 percent of the public favor the legislation, why not?”

Indeed, a Gallup poll taken last year said half of Americans surveyed favored the legalization of marijuana use, up from 46 percent in the previous year.

This is uncharted territory, though, and if the initiatives go through they would put those states in direct conflict with federal law. Lawyers say it is hard to predict how this would play out, but it could result in a federal crackdown.

In fact, it is unclear exactly how whoever becomes president will react. In April 2012, Obama said at a summit of Latin American leaders, “I don’t mind a debate around issues like decriminalization,” though he added, “I don’t think that legalization of drugs is going to be the answer.”

Romney has a long record of opposing the use of marijuana.

Opponents of legalizing marijuana say that it is dangerous drug, particularly when it falls into the wrong hands. They also argue it is an “entry level” drug that paves the way to more addictive substances.

Today, voters in three additional states — Arkansas, Massachusetts and Montana — will also decide on measures to allow for the therapeutic use of cannabis by patients with qualifying ailments.

Follow Kunbi Tinuoye on Twitter at @Kunbiti