Today, Bernie Sanders introduced the Medicare for All Act of 2019 into the Senate with fourteen co-sponsors. The single-payer proposal presents a clear alternative both to Donald Trump’s attempts to dismantle the Affordable Care Act and the Democratic leadership’s stubborn insistence on reforming it incrementally.

As with its 2017 version, the bill would cover all US residents under a single, public insurer, replacing the patchwork system we have today. It eliminates all premiums, co-pays, and deductibles while giving patients complete freedom of choice in doctor and hospital by doing away with network restrictions. And it covers a wide range of services including dental, vision, hearing, and reproductive care.

The new bill goes further than its predecessor: it now covers home- and community-based long-term care, which will allow people with disabilities to receive care at home without fear of financial bankruptcy or being forced into an institutional setting.

Like its companion legislation in the House, Sanders’s bill would ensure that people have stable and secure health care when they need it for the entirety of their lives, no matter their age, employment status, treatment needs, or prior health history. It would erase all financial stress in time of illness, as well as the headache of fighting with insurance companies and being forced to move from plan to plan.

The Medicare for All Act represents a kind of politics never yet realized in the United States: one that puts human needs over industry profits by guaranteeing universal benefits with no means-testing or exclusions.

This is the bill Sanders wants to sign into law as president. His current standing as the presidential frontrunner makes this an actual possibility, but also presents Sanders with a new set of challenges.

Sanders’s 2016 campaign sparked a surge in popularity for Medicare for All. In the three years since, it has grown from a distant progressive dream into a mainstream policy proposal with a burgeoning grassroots and labor movement behind it. It now carries sixty-three endorsements from national organizations and unions, more than double the number from 2017. But with 2020 approaching, the fight for Medicare for All is about to face unprecedented opposition.

Insurance and pharmaceutical interests, shielded by Democratic leadership, are ramping up their fight against Medicare for All. They’ve introduced a slew of competing proposals, launched big-money media campaigns targeting bill co-sponsors in their home districts, and lured a number of Sanders’s primary challengers into either rejecting Medicare for All outright — like Beto O’Rourke — or walking back their support into ambiguous territory. Such is the case with Kamala Harris, Cory Booker, and Kirsten Gillibrand — all of whom co-sponsor Sanders’s bill while supporting competing legislation on the side — and with Elizabeth Warren, who now says she supports multiple paths to universal coverage.

Meanwhile, Trump and Nancy Pelosi are parroting industry lies designed to frighten people into sticking with the devil they know: Medicare for All is “too expensive,” it’s going to “take freedom of choice out of health care,” and it will throw millions of Americans off their “beloved private health insurance.”

But Medicare for All will always win on the policy merits. Pelosi’s plan to reform the ACA will continue to leave millions uninsured; Medicare for All will cover every American resident as a right. O’Rourke’s Medicare for America plan will saddle patients with thousands of dollars in out-of-pocket costs; Medicare for All will make health care free at the point of use. Trump’s plan to stick with the current system will cost $42.9 trillion over the next ten years; Medicare for All will cost $5.1 trillion less.

The 2020 campaign is going to be a referendum on single payer, and it’s looking more and more like Sanders is the only candidate firmly committed to the idea. Winning will give him a clear mandate to pursue his signature policy as president. To do so, he’ll have to mobilize millions of people to confront the wealth and power of corporate interests and refute the lies they’re spreading. Sanders just threw down the gauntlet with his strongest bill yet. Now it’s time to join the fight.