(CNN) -- Marijuana is moving on "greased tracks" toward legalization, according to the advocacy group that's been riding the train for more than 40 years.
The reason is a stark shift in public opinion, said Allen St. Pierre, executive director of the National Organization for the Reform of Marijuana Laws. On Tuesday, Portland, Maine, followed Washington and Colorado's lead and legalized recreational use of the drug, while the Michigan cities of Lansing, Jackson and Ferndale resoundingly voted to let people older than 21 possess an ounce of the green stuff on private property.
The municipal votes may seem like small potatoes, but St. Pierre said that 2013 isn't just an off-year for elections, it's an "off-off-year."
"I absolutely pinch myself every single day, affirming that these changes are happening and they appear long-lasting," he said.
In Colorado, where voters OK'd recreational use in last year's election, another measure to tax marijuana -- opposed by some pot proponents -- also passed Tuesday.
"Here on K Street, that's a victory," he said, referring to the lobbyist row in Washington where NORML is headquartered. "(Not taxing marijuana) would've created a whole heap of mess with the federal government. Institutionally, strategically speaking, marijuana isn't going to become legal if it's not being taxed."
While public opinion on legalization has changed drastically since the 1960s, St. Pierre notes there has been an unprecedented spike in approval ratings just in the past year, reaching 58%, according to a Gallup Poll last month. The number marks a 10% increase since Colorado and Washington voted to legalize it, "and the legal momentum shows no sign of abating," according to Gallup.
Federal legalization isn't necessarily imminent, but the Justice Department seems to lack the appetite to take down Colorado and Washington, which it could easily do under the current U.S. Code. In September, Sen. Patrick Leahy held a hearing on the conflicts between state and federal laws after Deputy Attorney General James Cole issued a memo saying the feds would stand down in all but a handful of instances when it came to state marijuana laws.
"That absolutely supercharged states around the country -- to use a bad pun here -- to say, 'We have a green light,' " St. Pierre said.
St. Pierre, who has been with NORML for 23 years and has served as its director since 2005, said he's witnessed a "total sea change in the time I've been here."
Six years ago, politicians were returning NORML's donations, he said. Today, they not only accept them, but request them -- along with endorsements and assistance writing marijuana-related legislation.
There's even a bipartisan group of legislators St. Pierre calls the "cannabis caucus," which includes Reps. Jared Polis, Earl Blumenauer and Dana Rohrabacher and Sens. Rand Paul and Sheldon Whitehouse.
What's lighting the fire?
Though the tidal shift in public opinion is largely due to economics -- people think, "Schools, bridges, arresting people for marijuana -- which one can we compromise on today?" -- there are a host of reasons for the rapid change in opinion, he said.
Not only are sheer demographics playing a role, as the Brookings Institution pointed out earlier this year, but proponents have also concentrated on limiting access, public safety, rigorous alcohol-like enforcement and ensuring tax dollars are directed to the public good -- issues which appeal to women, who have historically been less opposed than men to pot prohibition, St. Pierre said.
It also didn't hurt that that a "popular, ethical doctor," CNN's Sanjay Gupta, issued in August a mea culpa for denouncing marijuana's viability in the past, St. Pierre said.
The same week Gupta reversed his stance on medical marijuana, Attorney General Eric Holder announced an initiative to curb mandatory minimum drug sentences and a federal judge called New York City's stop-and-frisk policy unconstitutional, indicating an opinion shift on national drug policy in general. (A federal court reinstated stop-and-frisk last week while appeals are heard).
Experts told CNN then that the nation had moved from the abstract matter of "if" to the more tangible debate over "how."
"Between Attorney General Holder's announcement, the decision made on stop-and-frisk and Dr. Gupta coming out with his documentary, it was a big week for drug policy," Beau Kilmer, co-director of the RAND Drug Policy Research Center and co-author of "Marijuana Legalization: What Everyone Needs to Know," said in August.
Peruse the Marijuana Majority website and you'll see decrying pot prohibition is no longer confined to the convictions of Cheech and Chong.
Today's debate involves an unlikely alliance that of conservatives Pat Robertson and Sarah Palin and rapper Snoop Lion (aka Snoop Dogg), blogger Arianna Huffington and Jon Stewart of "The Daily Show."
In June, the U.S. Conference of Mayors cited organized crime, a national change in attitude, the efficacy of medical marijuana and exorbitant costs to local governments in its resolution supporting "states setting their own marijuana policies," a stance similar to the one endorsed by the National Lawyers Guild and the Red Cross.
"I'm surprised by the long-term increase in support for marijuana legalization in the last six or seven years. It's unprecedented. It doesn't look like a blip," said Peter Reuter, a University of Maryland public policy professor with 30 years experience researching drug policy.
Reuter, who co-wrote the book "Cannabis Policy: Moving Beyond Stalemate," said he believes two factors are spurring the shift in national opinion: Medical marijuana has reduced the stigma associated with the drug, making it "less devilish," and the number of Americans who have tried the drug continues to rise.
When Washington and Colorado legalized pot, opponents weren't able to raise the money to derail the initiatives, which Reuter considers an "important signal that the country is no longer willing to fight this battle."
As important as the lack of resistance, Reuter said, is the subsequent response.
Though he doesn't see federal legalization on the horizon, he noted that the White House could easily shut Washington and Colorado down, either via a Justice Department crackdown or an IRS prohibition on tax deductions for the purchase of marijuana, which Reuter said would be a "killer for the industry."
Yet Holder and Congress were reticent until the Justice Department issued its memo and Leahy held hearings a year later.
"It may be that everyone's waiting to see what happens," Reuter said in August. "I take their silence to be some form of assent."
In 1969, a Gallup poll showed 12% of Americans supported pot legalization, and it estimated that same year that four in 100 Americans had taken a toke. In August, Gallup reported that number had spiked to almost four in 10.
Gallup, Pew and CNN/Opinion Research Corp. polls conducted in the past three years indicate a nation evenly divided until last month's surge in approval ratings, and Gupta's documentary planted him among a loud chorus that has sung the drug's praises since California approved medical marijuana in 1996.
Since then, 20 other states and the District of Columbia have passed similar laws, while Colorado and Washington state allowed recreational use -- a move Alaska, California, Nevada and Oregon each twice rejected between 1972 and 2010, according to the National Conference of State Legislatures.
Sixteen states have decriminalized possession of personal amounts of marijuana since 1973, including Colorado, which approved decriminalization 37 years before voters legalized cannabis in 2012, NORML says.
Mark Kleiman, a UCLA public policy professor who has been tapped to mold Washington's legal pot industry, noted in August that even in states where recent ballot initiatives were shot down, there are telling results. Perennial red state Arkansas' medical marijuana vote in November, for example, was a squeaker, failing 51% to 49%.
"When 49% of voters in Arkansas are voting for legal pot, we aren't in Kansas anymore," said Kleiman, who co-wrote "Marijuana Legalization" with Kilmer.
A savvier debate
The tone of the debate is also a sign that the country is nearing a tipping point at which public opinion effects political change. Rather than engaging in a simple yes-vs.-no debate about legalization, proponents are asking more nuanced questions: Should "grows" be large or small? What should the tax structure look like? Should potency be limited? Will the model involve for-profit companies? How will weed be distributed?
"The discussion over time -- and I think it's for the better -- the discussion is starting to focus more on the details," Kilmer said. "Before, nobody has ever really had to confront those decisions. ... Those decisions are really going to shape the cost and benefits of policy change."
The office emphasizes that the administration's 2013 drug policy takes a new tack with the realization that America can't arrest its way out of its longtime drug epidemic.
The White House policy, announced in April, favors prevention over incarceration, science over dogma and diversion for nonviolent offenders, the office says. Arguments for marijuana legalization, however, run counter to public health and safety concerns, the ONDCP says.
The federal government may have a difficult time maintaining its stance, experts predict.
John Kane, a federal judge in Colorado, said in December he sees marijuana following the same path as alcohol in the 1930s. Toward the end of Prohibition, Kane explained, judges routinely dismissed violations or levied fines so trivial that prosecutors quit filing cases.
"The law is simply going to die before it's repealed. It will just go into disuse," Kane said. "It's a cultural force, and you simply cannot legislate against a cultural force."
Kleiman, who is also chairman of the board for BOTEC Analysis Corp., a think tank applying public policy analysis techniques to the issues of crime and drug abuse, said the federal government may have tripped itself up in the 1970s by classifying marijuana as a Schedule I drug with no medicinal use and a high potential for abuse.
If the government had made it Schedule II, the classification for cocaine and oxycodone, 43 years ago, it would be easier today to justify a recreational ban, he said.
States to take lead
Kleiman said in August the infrastructure he is helping establish in Washington could provide a model for other states, but ideally, he'd prefer a model that involved federal legalization and permitted users to either grow their own marijuana or patronize co-ops.
"All the stuff I want to do you can't do as long as it's federally illegal," Kleiman said. "By the time we get it legalized federally, there will be systems in place in each state," which will make uniform controls at a national level tricky.
The push for legalization has gained momentum, though, he said, and he doesn't foresee it moving backward. In 10 years, proponents might even move politics at a national level, he said, though predictions are problematic so long as pot prohibition endures.
"It's sustained right now. Whether it's going to be sustained is another question," he said.
In the meantime, states are expected to continue to lead the charge. Alaska could put a legalization ballot before voters next year, while Maine, Rhode Island, and California may give it a shot in 2016, when the presidential election promises to bring younger voters to the polls.
In August, experts said Oregon could give it a go in 2016 as well, but NORML's St. Pierre said a recent influx of heavy checks from influential backers will land it on the ballot next year.
"I think a lot's going to depend on how legalization plays out in Colorado and Washington -- also, how the federal government responds," Kilmer said. "We still haven't heard how they're going to address commercial production facilities in those states."
The next White House administration could easily reverse course, just as it could on mandatory minimums, Kilmer said, but while pot's future is nebulous, the nation's change in attitude -- not only since the 1960s, but even since last year -- is clear. That makes proponents hopeful, if reluctant to make predictions.
"I didn't see this (shift in opinion) coming, and I think that's true of my collaborators," Reuter said. "So much for experts."