A few years ago, the notion that voters in the United States would opt to legalize recreational marijuana seemed wholly absurd. That was for Amsterdam, not America.

But in November 2012, citizens in Colorado and Washington defied conventional wisdom and overwhelmingly voted to end their prohibitions on cannabis. Other states followed suit in 2014 and even more look poised to do so next year.

Now, organizers in Colorado are hoping the state can be a trailblazer again by convincing voters to pass another policy many experts consider a pipe dream: free statewide healthcare.

Colorado’s secretary of state, Wayne Williams, announced this week that ColoradoCare, a citizen initiative to implement a single-payer healthcare system in the state, had submitted enough valid signatures to qualify for the November 2016 ballot. The group turned in 158,831 signatures, far surpassing the 98,492 required. The initiative is tentatively titled Amendment 69.

“Coloradans will have a chance to replace government and multinational corporate control of our health and our health care money with user-friendly, bureaucracy-lite, fiscally responsible financing,” ColoradoCareYES, the advocacy group behind the initiative, triumphantly declared in an email after Williams’s announcement.

If passed, ColoradoCare would create a single-payer system to provide health coverage for all residents of Colorado. It would be the first state to opt out of the Affordable Care Act and replace it with universal coverage.

Under the proposal, any time a Coloradan is billed for a healthcare service, they would simply forward that claim to ColoradoCare, which would foot the bill. Some services may require a small co-payment, but deductibles would be done away with altogether.

If that sounds similar to Medicare, that’s because it is. Like Medicare, all Coloradans would be required to pay into ColoradoCare, and thus be entitled to its benefits. However, just as senior citizens are free to buy supplemental health insurance or skip Medicare altogether if they choose, residents of Colorado would be free to do the same with ColoradoCare.

One prominent supporter of the plan is Senator Bernie Sanders. “Colorado could lead the nation in moving toward a system to ensure better healthcare for more people at less cost,” the Democratic presidential candidate told the Colorado Independent. “In the richest nation on earth, we should make healthcare a right for all citizens. No one should go bankrupt or skip getting the care they need because they cannot afford it.”

ColoradoCare would be paid for through a mix of federal Obamacare and Medicaid funding, as well as a 10% payroll tax increase. One-third of this “Health Care Premium Tax” would be assessed on individuals, with employers footing the other two-thirds.

Opponents have already blasted the plan as a $25bn income tax hike. Advancing Colorado, a conservative group that Colorado Democrats claim has ties to the Koch Brothers, blasted the initiative in a press release: “ColoradoCare will triple our taxes, lead to rationing of health care and will make Colorado a less attractive state for Millennials, businesses and families.

“Coloradans do not want to see their taxes triple and all the progress with health care reform thrown in the trash for a single-payer health care system. We can get more people covered, more affordably and more realistically with market-driven reforms that ensure choice and options.”

TR Reid, the author of ColoradoCare, batted away these claims. “The average family is currently spending $400 to $500 per month on health costs,” or as much as 8% of the average monthly household income. “ColoradoCare would cost that family just $196 month,” he said, a flat 3.3% of their income that would be paid in taxes.

In other words, taxes would indeed go up, but ColoradoCareYES argues the average Coloradan’s healthcare expenses would go down even further and that everyone making $225,000 or less would pay less in the aggregate under ColoradoCare. Those making above that threshold would pay more.

In addition, ColoradoCare would actually cover everyone in the state, including the estimated 400,000 Coloradans who still lack health insurance under Obamacare. Unlike Obamacare, which denies benefits to undocumented immigrants, ColoradoCare would not deny care based on legal status. “Our view is that if someone is living in our state and sending kids to our schools and has a contagious disease, we should treat them like everyone else,” said Reid, who is the author of the New York Times bestseller, The Healing of America: A Global Quest for Better, Cheaper and Fairer Health Care.

Section 1332 of Obamacare allows states to opt out of the health reform law so long as the proposed replacement would provide coverage that doesn’t cost more and was at least as comprehensive. Single-payer is one idea that would satisfy these requirements, but no state has implemented such a system yet. Lawmakers in Vermont had considered converting to single-payer, but the proposal was ultimately scrapped last December.

According to an economic analysis commissioned by ColoradoCareYES, in 2019, Coloradans will pay $31.2bn in healthcare expenses for everything from premiums to deductibles and beyond. If ColoradoCare passes and takes effect in 2019, that overall cost of healthcare would be reduced to $26.7bn. Reid said he expects those savings to increase over time because a single-payer system wouldn’t have the incentive to increase fees that for-profit health insurers do.

As the name implies, ColoradoCare would only cover Coloradans. A patient would have to show Colorado residency in order to get their care covered by the system. If an Ohioan breaks his leg on an Aspen ski vacation, he would have to use his Ohio-based insurance plan to pay for treatment at a Colorado hospital.

State senator Irene Aguilar, a practicing physician and proponent of the measure, explained why the group is putting the measure to a citizens’ vote rather than the normal legislative procedure. “We’ve tried to pass ColoradoCare through the legislature, but with the money in politics these days, there’s just no chance,” she said in a video. “Fortunately in Colorado, we don’t have to wait for the legislature to get things done.”

Inaction in the legislature is what prompted proponents of marijuana legalization to take the matter to a citizens’ vote. And with success in Colorado and elsewhere, that legalization push is spreading across the country.

Could healthcare be next? “Some state has got to be brave enough to be the leader,” Reid said. “Why not Colorado?”