And, as Attorney-General Eric Holder tries to figure out how to respond to the new legalisation laws, the poll had more good news for voters in the two states: 60 per cent of Americans say the US government should not enforce federal drug laws in any state that has voted to legalise pot.
The poll found a strong consensus among people of all political persuasions for the federal government not to intervene: 64 per cent of those who identified as independents, 59 per cent of Democrats and 57 per cent of Republicans.
Overall, 52 per cent of Americans now say marijuana should be legal, while 45 per cent say it should remain illegal, according to the poll conducted in mid-March by the Pew Research Centre.
The centre said the results marked the first time in more than four decades of polling on the issue that legalised marijuana had won majority support.
More Americans are experimenting with marijuana, too, the poll found. Forty-eight per cent said they had smoked the drug, compared with 38 per cent a decade ago. And the poll found a sharp decline in the percentage of Americans who now believe that marijuana is a “gateway” drug that leads users to try other, harder drugs such as cocaine.
The poll found that 50 per cent of all baby boomers now back legalised marijuana, compared with only 17 per cent of boomers in 1990.
But it’s mainly younger Americans who are propelling the drive to legalise the drug, with 65 per cent of adults born since 1980 – now between the ages of 18 and 32 – known collectively as the Millennial Generation, backing the idea. That compares with just 36 per cent for the same age group five years ago.
The poll found that support for legalising marijuana rose by 11 points among all age groups since 2010. That’s a huge change since a 1969 Gallup survey found only 12 per cent backing legalised marijuana, while 84 per cent were opposed.
Another Gallup poll in December found 48 per cent of Americans backing legalised pot, while 50 per cent were opposed to the idea.
Reacting to the Pew poll, Steve Fox, national political director for the Marijuana Policy Project in Washington, DC, said marijuana prohibition “is a policy without a rational basis and without public support”.
“These results do not just represent a tipping point,” he said. With support for legalisation among people under age 50 at close to 60 per cent, he said, “This is more like the tip of the iceberg. Elected officials across the country need to listen to the people.”
Washington state and Colorado officials are proceeding with plans to open recreational dispensaries later this year, but both are awaiting a formal response from Holder on whether the federal government will try to stop them.
Holder is under fierce pressure from both sides, with marijuana opponents urging him to uphold the federal statutes and block the states from proceeding, while proponents want the Obama administration to stay out of the way.
Holder has given no indication how he will rule. But he told the Senate Judiciary Committee early last month that he would release an opinion soon, though he gave no specific time frame.