There’s little question that health care in America is expensive, but addressing this fundamental social issue has proved challenging. This coming Election Day (November 8), Colorado voters will have a chance to make a big change to our state’s health-care system, and the result could make history.

In the current system, most of us pay our medical bills through for-profit health insurance companies. Amendment 69, otherwise known as ColoradoCare, is a constitutional amendment that would create a universal health-care system in which the state pays most medical bills, funded in part by a large payroll tax levied on all residents.

It’s a similar idea to the single-payer system that Bernie Sanders called for nationally in his run for the Democratic nomination, and one that was attempted (and later abandoned) in his home state of Vermont in 2011. Sanders, who won Colorado’s Democratic caucus with nearly 59 percent of the vote, appeared in Boulder on Monday to campaign in support of the amendment. “The current American healthcare system is dysfunctional and it has to change,” Sanders told a crowd of more than 2,000 supporters at the University of Colorado’s Farrand Field. “Colorado can send a shot that will be heard all over the country and all over the world.”

But despite Sanders’ backing, the ColoradoCare measure is facing fierce opposition from many groups and individuals, including some Democrats and progressives. Voters have been lukewarm on the amendment, and on Tuesday, a poll released by Mercer—a global consulting company that specializes in health-care and investment options for businesses—found that 82 percent of Colorado-based employers believe the move would have a negative impact on their organizations.

So before deciding how to vote on this controversial and historic proposal, we answered nine questions about the amendment to help guide you:

What would it do if it passes?

ColoradoCare would officially launch in 2019, and give all state residents health-care coverage that would take the place of most private insurance. People with federal health coverage, like Medicare or the Veterans Health Administration, would continue using that as their primary coverage, and ColoradoCare would provide supplemental benefits. Some doctor visits would still involve copays, but there would be no more insurance deductibles or premiums.

The proposed state program would be run by an elected board of trustees, following the cooperative business model (meaning that it’s owned by its members, Colorado citizens, who elect the board). However it would be classified as a political subdivision of the state, and not subject to the direction of any government departments, agencies, or representatives. Board members are not required to have experience in health care or insurance, and will be responsible for hiring the team that will run the program.

Health-care costs would be paid for with money from federal government sources and—most notably—a new 10 percent payroll tax. Colorado employers would pay two-thirds of that (6.67 percent), and employees would pay one-third (3.33 percent). Self-employed individuals would pay the full 10 percent.

The new tax is projected to bring in almost $25 billion, which proponents say is less than what employers and employees are currently paying in health insurance premiums, deductibles, and out-of-pocket expenses. Individuals could still choose to buy private health insurance, but they would remain subject to the payroll tax for ColoradoCare.

What problems is it aiming to solve?

Proponents of Amendment 69 want to give everyone in Colorado quality health coverage. The Affordable Care Act cut our state’s uninsured rate in half, but just under seven percent of residents still lack health insurance. Backers also want to make health care more affordable, which they say they can do by having lower administrative costs than insurance companies and negotiating new payment rates with doctors, hospitals, and prescription drug providers.

Under the existing system, people who buy their health insurance on Colorado’s health-care exchange are bracing for 20 percent premium hikes, on average, in 2017. And a recent Kaiser Family Foundation report revealed that even people who receive coverage through their employers have seen their deductibles rise nearly six times as fast as wages in the last five years.

So what’s the big controversy?

The cost, primarily. While a 10 percent tax increase up front is notable, a key issue with the amendment is that the cost of health care nationwide is rising—under the Affordable Care Act, it’s risen more slowly than it once did, but it’s still going up—which means that Coloradans can likely expect to vote on an increase for this health-care tax in the future.

An independent financial analysis by the nonpartisan Colorado Health Institute found that ColoradoCare would likely break even in its first year and would succeed in reducing total health-care spending in its first decade. But analysts predicted that health care costs would eventually catch up, and the program could be nearly $8 billion short by year 10 (a prediction the proposal’s backers dispute). Of course, voting down the measure won’t keep health-care costs from rising. It will just mean that Coloradans will continue paying them via the existing health insurance system.

Critics of ColoradoCare note the program’s projected annual cost—$25 billion—is about 50 percent larger than the state’s current annual budget. They say the 10 percent payroll tax would be too burdensome to employers and would encourage them to leave or avoid the state. In fact, the Mercer poll found that about a third of respondents would be less likely to expand business operations in the state if the amendment passes.

Opponents also fear that health-care providers might leave if the reimbursements aren’t sufficient, and that there might be an influx of people moving to Colorado because they’re attracted to the guaranteed health coverage, adding strain (and costs) to the system. There’s also a chance that voters will refuse to increase the taxes on the program if needed. On the flip side, if revenues exceed expectations, taxpayers won’t be eligible for a refund because the program will be exempt from the Colorado Taxpayers Bill of Rights.

Would my specific prescription/medical device/procedure be covered?

This question is harder to answer. The ColoradoCare campaign’s communications director, Owen Perkins, said the program has all the mandatory coverage requirements that insurance plans have under the Affordable Care Act. He said it will cover everything Medicare covers, at a minimum, and likely more. But the language of the constitutional amendment does not include an exact list of the medications, devices, and procedures that will be covered—or how much they will cost consumers. Creating that will be up to ColoradoCare’s 21-member elected board of trustees.

Has any other state done this?

Not successfully. In 2011, Vermont Governor Peter Shumlin attempted to create a single-payer system in the state, but he abandoned the concept three years later, before it went into effect. “In my judgment,” he said in a statement, “the potential economic disruption and risks would be too great to small businesses, working families, and the state’s economy.”

One key difference between Vermont’s single-payer attempt and ColoradoCare is that ours would be a state constitutional amendment. In other words, if we passed it and eventually don’t like it, it would take more than a gubernatorial proclamation to kill it.

If we pass this, does it mean we’re repealing the Affordable Care Act?

Not really. It’s true that implementing Amendment 69 would replace the state health insurance marketplace, Connect for Health Colorado, which was created under Obamacare. (It would ostensibly replace all other private health insurance, too.) But, in order to operate, ColoradoCare would actually have to get a waiver from the federal government saying it achieves the aims of Obamacare.

Is this like Bernie Sanders’s ‘Medicare for All’ idea?

Sort of. It’s the single-payer concept on a much smaller scale, and Bernie Sanders officially endorsed it in August. In his speech at CU Boulder on Monday, Sanders urged voters to, “Stand tall and vote yes on Amendment 69,” saying that “millions of people are watching what you do.” But when Sanders’s home state of Vermont attempted its single payer plan in 2011, one of the criticisms was that a state can’t achieve a true single-payer program because so many of its residents are primarily covered by various federal health-care programs. (In Colorado, it’s about 17 percent of our 5.4 million people.)

Who’s in favor of this amendment?

As noted above, the measure has Bernie Sanders’ endorsement, as well as Rep. Joe Salazar, Rep. Jonathan Singer, and Sen. Irene Aguilar, a physician who was one of the measure’s main architects. These local officials appeared with Sanders on Monday and spoke in support of the measure. Activists such as Gloria Steinem and Noam Chomsky are also on board, as well as 175 organizations, including the League of Women Voters of Colorado, the Colorado Democratic Party Platform, and the Public Health Nurses Association of Colorado.

Who’s against it?

Unsurprisingly, the health insurance industry doesn’t like this proposal. The Colorado Medical Society also came out against it in late September. Perhaps more unexpectedly, some prominent Colorado Democrats don’t favor ColoradoCare, including Gov. John Hickenlooper, Sen. Michael Bennet, former Gov. Bill Ritter, and liberal activist group ProgressNow Colorado.

Recent campaign finance filings show Coloradans for Coloradans, the amendment’s main opposition group, has out-fundraised the ColoradoCare campaign more than 10:1, thanks largely to its insurance industry backers. Lastly, Colorado citizens are unenthusiastic about the proposal. A poll released in September found that 65 percent of those surveyed would vote against the measure, while 27 percent supported it, and 8 percent were undecided. It remains to be seen if Sanders’ progressive star-power will be enough to sway public opinion before Election Day.