Voters in Colorado, Oregon and Washington are all considering measures that would effectively end marijuana prohibition in their respective states. Marijuana legalization has become an issue that defies the stereotypes of party lines, garnering the support of key progressives and conservatives in Colorado, Washington and Oregon. And although all three states have pot initiatives on their ballots, Colorado and Washington's pot ballot measures appear to be quite popular with voters, according to recent polling.

If marijuana is legalized in Colorado under Amendment 64 it would be taxed and regulated similar to alcohol and tobacco. It would give state and local governments the ability to control and tax the sale of small amounts of marijuana to adults age 21 and older. According to the Associated Press, analysts project that that tax revenue could generate somewhere between $5 million and $22 million a year in the state. An economist whose study was funded by a pro-pot group projects as much as a $60 million boost by 2017.

However, the big unknown still is if the federal government would allow a regulated marijuana market to take shape. Attorney General Eric Holder, who was a vocal opponent of California's legalization initiative in 2010 saying he would "vigorously enforce" federal marijuana prohibition, has continued to remain silent on the issue this year.

In September, Holder was urged by by nine former heads of the U.S. Drug Enforcement Administration to take a stand against marijuana legalization again. "To continue to remain silent conveys to the American public and the global community a tacit acceptance of these dangerous initiatives," the nine said in the letter to holder obtained by Reuters.

Peter Bensinger, the moderater of the call and former administrator of the DEA during President Gerald Ford, Jimmy Carter and Ronald Reagan administrations, began the call. "Federal law, the U.S. Constitution and Supreme Court decisions say that this cannot be done because federal law preempts state law."

Bensinger added: "And there is a bigger danger that touches every one of us -- legalizing marijuana threatens public health and safety. In states that have legalized medical marijuana, drug driving arrests, accidents, and drug overdose deaths have skyrocketed. Drug treatment admissions are up and the number of teens using this gateway drug is up dramatically."

Bensinger was joined by a host of speakers including Bill Bennet and John Walters, former directors of the While House Office of National Drug Control Policy; Chief Richard Beary of the International Association of Chiefs of Police (IACP); Dr. Robert L. DuPont, founding director of the National Institute on Drug Abuse (NIDA) and who was also representing the American Society of Addiction Medicine (ASAM) and several others.

Researchers looked at marijuana use among youth between 1993 and 2009, a time when 13 states legalized the drug for medical use. They found no correlation between legalization of the drug and increased use among teens in a given state.

In fact, slight drops in teen use were seen in some states where marijuana was legalized.

"We are confident that marijuana use by teenagers does not increase when a state legalizes medical marijuana," said study researcher D. Mark Anderson, assistant professor of health economics and risky behavior at Montana State University.

The researchers used data from the Youth Risky Behavior Survey, conducted by researchers at the Centers for Disease Control and Prevention. The survey collects self-reported data from a nationally representative sample of high school students on various risky behaviors.