If Democrats win a smashing victory in the 2020 elections — an unlikely but not totally far-fetched scenario — they’ll start the next year with the House, the Senate and the presidency. They’ll have a popular mandate. But in large part because of Mitch McConnell’s machinations — including the blockade of the Supreme Court nominee Merrick Garland on patently specious grounds — they’ll face a court even more conservative than the one that neutered the Medicaid expansion (one of the most important features of the Affordable Care Act) and gutted the Voting Rights Act during President Barack Obama’s eight years in office.

Under Obama, the median vote on the court belonged to Justice Anthony M. Kennedy. With his retirement, it now belongs to Chief Justice John Roberts, a reliable conservative on major issues like civil rights, criminal justice and executive power. Roberts dissented in the case that legalized same-sex marriage, voted to allow the death penalty even in cases where it might cause excruciating pain and suffering, and wrote the majority opinion upholding Trump’s travel ban despite its clear roots in the president’s anti-Muslim bias. His Republican-nominated colleagues — Clarence Thomas, Samuel Alito, Neil Gorsuch and Brett Kavanaugh — are farther to the right, with Thomas ranking among the most conservative justices to ever sit on the court.

Their collective hostility to liberal governance (and in Thomas’s case, the entire New Deal order) virtually guarantees that there will be a series of constitutional confrontations if and when Democrats have a chance to shape and revitalize the social safety net, just as there was in the 1930s. And that’s to say nothing of the lower courts, stacked with dozens of conservative judges under Trump. A president supported by a minority of voters may shackle future majorities f or decades to come.

Will this stronghold of conservative jurists stay its hand as Democrats embark on their plans and agenda items? Or will these judges strike back, curtailing the policies of the Democratic majority and trimming the sails of its ambition, forcing the public to conform to their particular understanding of the Constitution despite equally valid alternatives? Will Democrats, in other words, relive the experience of Franklin Roosevelt’s first term, stymied by judges and justices whose vision of “liberty” rejects the right of the people to shape their collective economic lives?

What lies over the horizon isn’t just a fight over the meaning of the Constitution; it’s a fight over the power to interpret it. Right now, it appears that power rests with the Supreme Court and its conservative majority. But past presidents have contested the court’s predominance, both before and after winning the presidency; they’ve challenged the idea that its decisions constitute, as Abraham Lincoln said speaking against the Dred Scott ruling during one of his debates with Stephen Douglas, a “rule of political action, for the people and all the departments of the government.” They’ve declared, as Andrew Jackson argued when he vetoed the Second Bank of the United States, that they will support the Constitution as they understand it, “not as it is understood by others.”

Progressives have a crucial task ahead of them — not merely to defeat Trump and Trumpism, but to reclaim the Constitution and advance a more expansive vision of democratic freedom, in which Americans have inalienable economic rights as well as inalienable political and civil ones. It’s a problem of power, which means it’s impossible to fight this conflict with Buttigieg-style technocratic reforms. Progressives must look, instead, to presidents and other leaders who resisted the Supreme Court’s claim to ultimate interpretive authority. And they must insist, as Lincoln did, that the people of the United States are their “own rulers.”