When asked recently about the soon-to-be-negotiated stimulus bill, Bernie Sanders said he wouldn’t use his new position as Senate Budget Committee chairman to push for his entire agenda, including Medicare for All. But that doesn’t mean he’s backing down from an aggressive working-class agenda. Sanders’s keystone proposal for the stimulus, the Health Care Emergency Guarantee Act (HCEGA), is essentially Medicare for All on an emergency, temporary basis.

It’s the right fight to pick with President Biden — and a test of what the resurgent left can accomplish under the new administration.

Sanders’s plan would guarantee that every person in the United States, regardless of employment, immigration, or insurance status, has the health care they need — including free testing, vaccines, and treatment — during the COVID-19 pandemic. Simple, comprehensive, and cost-effective, the plan would empower Medicare to pay all medical bills including prescription drugs. Patients could go to any hospital or doctor they wanted to, free of cost. The immediate benefits to workers would be enormous: no more worrying about bills, no more choosing between health care and other essentials.

Along with making coverage universal, the bill would deliver other massive perks. First, it would solve one of the biggest challenges in confronting COVID-19: people afraid of high health care costs delaying treatment, leading to more transmissions and more deaths. The legislation would also halt medical debt collections, prohibit private insurance companies from increasing cost-sharing, and require ongoing data collection and weekly reporting on COVID-19–related health disparities. And by using Medicare, the legislation would immediately free health care providers from the onerous administrative responsibilities of dealing with private insurance. Nurses and doctors could finally spend all their time treating infected patients, rather than wrangling with insurers.

As Senate budget chair, Sanders is in one of the best positions to negotiate for including the HCEGA in the multi-trillion-dollar stimulus bill. He has the power to pass the relief bill through reconciliation, circumventing the filibuster by lowering the voting threshold in the Senate to a simple majority. With fifty senators and the vice president as the tiebreaker, Democrats have every vote they need to guarantee universal health care during this pandemic. They just have to use it.

In stark contrast to Sanders’s proposal is Biden’s industry-crafted plan, which proposes expanding COBRA through subsidies. COBRA covers workers who have lost their health insurance as a result of being laid off or having their hours reduced. Biden, alongside other centrist Democrats, wants to boost subsidies so enrollees “will not pay more than 8.5 percent of their income for coverage.” Those who enroll in COBRA would continue to be hit with the high deductibles of their job-based plans (roughly $1,800 on average). Biden’s plan does nothing to cover those who already lacked job-based insurance plans, leaving millions uninsured.

We need a response to the pandemic that supports the underinsured and the uninsured alike. Even those with strong union-negotiated plans shouldn’t have to worry about co-pays, deductibles, or prescription costs. And if only some of us can afford treatment, COVID-19 will continue to threaten all of us. The only winners from subsidizing COBRA are the private insurance companies who would rake in the subsidies. Biden’s COBRA proposal promises to line their pockets with hundreds of billions of dollars in windfall profits.

Sanders’s emergency legislation, despite being temporary, could also pave the way for the permanent solution of single-payer. Just like Medicare for All, the HCEGA would be a publicly financed and administered universal program that eliminates out-of-pocket costs and removes barriers to care. It would demonstrate the practical viability of Medicare for All and prove that the government could work to meet people’s needs. Those with shoddy private plans would experience the wonders of good health insurance, making it harder to take their benefits away and easier to mobilize a constituency around single-payer. Finally, the process of organizing for Sanders’s emergency health care program could generate momentum for the Medicare for All movement, bringing more people into the fold actively fighting for Medicare for All.

With his new proposal, Bernie Sanders is creating a strategic opening: a politically viable democratic socialist vision of urgently needed pandemic relief that challenges Democratic leadership head-on and gets us qualitatively closer to Medicare for All. The HCEGA is the most comprehensive and cost-effective way to guarantee that everyone gets the health care they need, without cost, for the duration of the pandemic.

It’s now up to union activists, socialists, and progressives across the country to take up Sanders’s rallying cry. Failure to act could risk spoiling what favorable conditions we have in this brief window of opportunity.