“We feel that if Oregon or Alaska could be stopped, it would disrupt the whole narrative these groups have that legalization is inevitable,” said Kevin A. Sabet, executive director of Smart Approaches to Marijuana, which is spearheading much of the effort to stop these initiatives. “We could stop that momentum.”

Despite the drug still being illegal under federal law, the Obama administration has said it will not interfere with the rollout of legal marijuana in the states for several reasons, including whether the state is successful in keeping it out of the hands of minors.

At least 14 states — including Florida, where an initiative has already qualified for the ballot — are considering new medical marijuana laws this year, according to the Marijuana Policy Project, which supports legalization, and 12 states and the District of Columbia are contemplating decriminalization, in which the drug remains illegal, but the penalties are softened or reduced to fines. Medical marijuana use is already legal in 20 states and the District of Columbia.

An even larger number of states, at least 17, have seen bills introduced or initiatives begun to legalize the drug for adult use along the lines of alcohol, the same approach used in Colorado and Washington, but most of those efforts are considered unlikely of success this year.