"It's safe to say that no other reform was approved by so many citizens on so many ballots this year"

On a dismal election night, voters in four lucky states found something progressive to celebrate—recreational marijuana legalization.

California, Maine, Massachusetts, and Nevada all voted to make it legal for adults over 21 to smoke weed, a sweeping mandate that many expect will prompt a legislative domino effect throughout the country.

Nowhere is that felt more strongly than in the politically influential state of California. Advocates have long said that if legalization passed there, other states would be likely to follow suit. Both California and Nevada's wins also help strengthen a West Coast "marijuana bloc," as the New York Times put it, joining Alaska, Washington, Colorado, and Oregon in making recreational use legal in their states and throughout the region.

Arizona, the final state considering full legalization, narrowly rejected its ballot measure. Medical marijuana remains legal in the state, however.

"Marijuana reform won big across America on Election Day—indeed it's safe to say that no other reform was approved by so many citizens on so many ballots this year," said Ethan Nadelmann, executive director of the advocacy group Drug Policy Alliance (DPA), although he also cautioned that the election of Donald Trump threatens the advances made on Tuesday.

"The momentum for ending marijuana prohibition took a great leap forward with the victories in California and elsewhere, but the federal government retains the power to hobble much of what we've accomplished. The progress we've made, and the values that underlie our struggle—freedom, compassion, reason, and justice —will be very much at risk when Donald Trump enters the White House," he said.