As polls show record support for marijuana legalization, advocates say the midterm elections could mark the point of no return for a movement that has been gathering steam for years.

“The train has left the station,” said Rep. Earl Blumenauer, D-Ore., a leading marijuana reform advocate in Congress. “I see all the pieces coming together… It’s the same arc we saw two generations ago with the prohibitions of alcohol.”

Voters in four states will weigh in on ballot initiatives to legalize weed for recreational or medical use next month, while voters everywhere will consider giving more power to Democrats, who have increasingly campaigned on marijuana legalization and are likely to advance legislation on the issue if they win back power in Congress and state capitals.

It’s been just six years since Colorado and Washington became the first states in the country to legalize marijuana, but in that short time span, seven other states and the District of Columbia have followed. Thirty states have legalized medical cannabis. The entire country of Canada legalized the drug last week. [Read more at NBC News]