Former Democratic presidential candidate Bernie Sanders will be in Boulder on Monday at the University of Colorado to campaign in support of Amendment 69, the statewide measure that would create a universal state-administered and financed health care system for Colorado residents.

The measure faces stiff opposition across the political spectrum, in large part because of the large payroll tax increases that would be required to fund the program, known as ColoradoCare. If passed, the state would become the first in the nation to offer a universal system.

Sanders, an independent U.S. senator from Vermont and Hillary Clinton’s rival in the Democratic primaries, will appear at Farrand Field at the University of Colorado at 5 p.m., according to the ColoradoYES campaign. Doors open at 4 p.m.

Sanders waged an insurgent campaign in the Democratic primary, casting himself as an outsider to entrenched political interests in Washington while offering messages that resonated in particular with young voters. He has advocated for a universal healthcare system paid through the federal government by Medicare. He won Colorado’s caucuses handily in March.

“It is absurd, it is beyond belief, that here in America we remain the only major country on earth not to guarantee health care to all people,” Sanders said at an event on Aug. 25, when he first came out publicly in support of Amendment 69. “If that proposal can win in Colorado, I believe that idea will spread around the country.”

In Sunday’s second presidential debate, Clinton acknowledged the shortcomings of the Affordable Care Act, which has come under assault because it hasn’t stemmed fast-rising healthcare premiums. Clinton advocated for repairing the existing law rather than throwing it out and starting over, as Republicans and GOP presidential nominee Donald Trump have argued must be done.

An independent analysis found in the short-term, the measure could work. But by its 10th year, the study from the Colorado Health Institute said the program would be $8 billion short of its revenue needs, with losses mounting as the cost of health care rises. To make up for the shortfall, voters would be asked to increase more taxes. ColoradoCareYES says the program would save $4.5 billion a year in health care costs while saving average Coloradans thousands of dollars. Supporters say elected decision-makers to a 21-person board would offer transparency and improve patient care.

A poll released in early September and conducted in late August found that only 27 percent of Coloradans support the measure, with 65 percent saying they would vote against it. Eight percent were undecided. That same survey did, however, show slightly more support among those 18-34 years old, with 59 percent against it and 40 percent for it, with 1 percent undecided.