Sen. Elizabeth Warren (D-Mass.) had a blunt message for her fellow congressional Democrats on Thursday as the party prepared to take control of the House and Senate: “Americans need Democrats to deliver now, not in two years.”

In a post-election assessment, Warren outlined how Democrats can use their impending majorities on Capitol Hill to deliver real gains for the working class—even with President Donald Trump in the White House.

Writing in an op-ed for TIME, Warren argued that Democrats succeeded in midterm contests across the country “by being populist economic fighters who were unafraid to call out the corrupt politicians and corporate interests who have rigged the system at the expense of everyone else.”

“Now, Democrats must deliver,” the progressive senator wrote, urging her party to push Trump to live up to his vow to work with Democrats in the new Congress. “We should force him to do that on the affordability and corruption issues that drove this election—or call his bluff.”

Warren laid out what she views as the top priorities for the new Democratic majority. Her list included ending Trump’s illegal war in Iran, cutting costs for working families, canceling the Trump-GOP cuts to Medicaid and nutrition assistance, reversing Trump’s tax cuts for the rich, and holding “Big Tech CEOs, Wall Street executives, and giant corporations” accountable for “ripping off the American people to make themselves richer.”

The senator expressed openness to working with Republicans but wrote that Democrats must be willing to use the filibuster-proof reconciliation process—or eliminate the Senate’s 60-vote filibuster entirely—to advance an ambitious agenda. The procedural distinction matters: most Senate legislation requires 60 votes to overcome a filibuster, while reconciliation, which is limited to provisions affecting the budget, can pass with a simple majority.

But what if Trump decides to wield his veto power against Democratic legislation, as he has suggested he could do?

Warren argued that Democrats must “test that out by passing legislation the American people support to make life more affordable and our government less corrupt.” Overriding a presidential veto, under the Constitution, requires a two-thirds vote in both the House and Senate—a threshold that shapes how much of any agenda can survive an opposed White House.

“It would be a breach of faith with the people from South Carolina to Texas, who voted for us to address costs and corruption, to spend the next two years waiting for some future Democratic trifecta to hopefully deliver meaningful change,” Warren wrote. “Democrats won this election by claiming we are on the side of working people, and working people are counting on us to deliver.”

Another leading progressive in the Senate Democratic caucus, Bernie Sanders (I-Vt.), similarly argued that Democrats’ historic midterm wins were “important,” but “not enough.”

“The American people want change. Real change. And the midterm election confirms just that,” Sanders said in a video message, pointing to the urgent need to address out-of-control income and wealth inequality, the starvation-level federal minimum wage, unfettered artificial intelligence, the corrupt campaign finance system, the broken for-profit healthcare system, and more.

The solutions to those crises, he argued, “are not radical,” pointing to broad public support for Medicare for All, expanding Social Security, and other progressive proposals.

“What we are talking about now is not only the need to fight for economic justice,” said Sanders. “We are fighting to give hope to the American people—to allow them to understand that their government can work for them, can address the crises that they face, and will pay attention to the needs of the men, women and children in our country who are struggling, and not just the very, very wealthy campaign contributors.”

“That is, in my view, what Democrats have got to do when they assume power in January,” he added. “We can do it. We must do it.”

The overlap between the two senators underscores the stakes facing the incoming Congress: holding majorities but not the presidency, Democrats’ decisions on reconciliation, the filibuster, and veto confrontations will shape what legislation reaches Trump’s desk. When the new term convenes in January, the markers to watch include whether the party pursues bipartisan deals with a president who has vowed cooperation, follows Warren’s urged path of testing his floated veto threats with broadly supported bills, or moves to alter Senate rules outright.

This article is based on reporting originally published by Alternet.