More and more, it seems like national marijuana legalization is happening, and happening fast. Marijuana is now legal in Colorado and Washington state, and state and local authorities around the country are rapidly following suit to decriminalize recreational pot or legalize its use for medical purposes. States like New Jersey are mulling legalizing the possession of small amounts of marijuana entirely.

But what’s behind this massive shift in drug policy opinion? Changing generational sensibilities. In a Pew Research Center poll released last week, Millennials were noted as overwhelmingly supportive of marijuana legalization at a stunning 69% rate, more than double their support as recently as 2005. And older generations have changed their minds as well; 53% of Gen X and 52% of Boomers now back changing federal laws.