After edging toward a political precipice two years ago, voters recoiled Tuesday and delivered Democrats a sweeping victory. With turnout surging among Hispanic, Black and young voters, Democrats flipped the House and Senate while winning seats the party had not captured in decades.

History favored Republicans losing their narrow House majority, but the scale of their defeat was hardly guaranteed. “This is shaping up to be the biggest House popular vote victory for any party since 1974,” MS NOW contributor G. Elliott Morris wrote, while MS NOW projected Democrats would hold at least 245 House seats in January.

Control of the Senate had been the larger uncertainty. After President Donald Trump’s inauguration, the Senate Republican campaign arm sought 55 seats, but by early Wednesday, Democrats had secured at least 54, including seats in Texas, Kansas and South Carolina.

For the first time during either Trump presidency, Democrats will control both chambers of Congress. That victory gives them the ability to pass legislation, conduct investigations and hold people inside and outside the White House accountable for abuses during the past two years.

Their first responsibility is protecting the election results from attempts to corrupt them. Justice Department lawsuits challenging election administration in California and Alaska have failed, but Trump could continue casting doubt on the results while his allies act as though the law places no limits on them.

Congressional Democrats must also remain vigilant during the lame duck session and try to block any final Republican legislative maneuvers. Once the new Congress takes office, voters will expect Democrats to move directly on the affordability crisis that helped shape the election.

That agenda should include reversing tariffs and cuts to SNAP and Medicaid, increasing the minimum wage and restoring the Biden era child tax credit. Democrats also have an opportunity to turn Medicare for All from a popular slogan into a concrete policy proposal.

One recent Yale study found that a single payer universal system would save Americans $1 trillion each year in health care spending and save 114,000 lives. Such legislation is unlikely to become law while Trump holds the veto pen.

Trump has already said he would “become Mr. Veto” if Democrats controlled the next Congress, and his willingness to compromise has fallen sharply since his first term. Still, passing these bills could help Democratic lawmakers build trust with voters who previously felt little enthusiasm for the party.

Democrats will also possess leverage through congressional control over spending. The House can demand influence over priorities ranging from ending the Iran war to stopping Trump’s vanity projects.

Rep. Jamie Raskin, D-Md., told The New Republic’s Greg Sargent that Democrats must carefully use appropriations authority to prevent violations of constitutional rights. They can pursue limits on politically motivated prosecutions, impose restrictions on Immigration and Customs Enforcement and challenge other elements of Stephen Miller’s white nationalist project.

That spending authority could also be used to end National Guard deployments to Washington, D.C., Memphis and other locations. With majorities in both chambers, Democrats will gain broader investigative and oversight powers even if the White House resists.

Possible inquiries include the Trump family’s business dealings, the administration’s handling of the Epstein files, corporate corruption and profiteering, and the conduct of the Iran war. Hearings could also support possible impeachment cases against Trump or Cabinet members, including War Secretary Pete Hegseth, although conviction and removal remain highly unlikely.

Hearings can expose any effort by Trump to use pardons as a shield for allies and staff members before investigations begin. Trump has also suggested he would consider pardoning Republican megadonor Elon Musk, another potential subject of Democratic investigations.

Senate Democrats should also refuse to confirm additional judges nominated by Trump, whether vacancies arise on the Supreme Court or lower courts. They should demand a new binding ethics code for the Supreme Court and reject nominees who will not even identify the winner of the 2020 election.

Above all, Democrats must remember the voters, protesters and everyday Americans who spent the past two years doing democracy’s hardest work. The damage inflicted by Trump will not disappear overnight, and Democrats’ choices will determine whether Tuesday becomes a brief flash of hope or the beginning of a new era.