Justice Anthony Kennedy recently announced his retirement after serving three decades on our nation’s highest court. During his tenure, Justice Kennedy was the decisive fifth vote in several landmark decisions that safeguarded marriage equality, criminal justice, and women’s health care. His successor will profoundly influence the future of American jurisprudence and our fundamental rights for decades.

There is great progress yet to be made before Equal Justice Under Law is more than mere words engraved on the Supreme Court building, but our victories from a generation ago are now at risk. The Supreme Court plays a critical role as the backstop when other institutions fail to protect people’s civil and human rights. The stakes of this vacancy are enormously high. Access to health care – especially for women – is most immediately under threat. During his political campaign, President Trump bragged that he would only appoint judges who would overturn Roe v. Wade and rule against the Affordable Care Act. His litmus test for a potential nominee is clear.

Every name Trump considered was selected by the ultra-conservative Heritage Foundation and Federalist Society to advance their ideological agenda. If any one of them is confirmed, we can expect the Court to undermine the Affordable Care Act, taking health care away from millions – disproportionally affecting women, people of color, people with disabilities, and low-income families.

Trump’s intention to transform the courts is not limited to the Supreme Court. Perhaps nowhere has the president cemented lasting hostility to civil rights more so than the federal courts. Far from the impartial jurists that our independent judiciary demands, Trump has nominated extremist ideologues with anti-civil rights records to lifetime seats on the district and circuit courts as well.

No one on Trump’s Supreme Court list is there because they are fair-minded. Their reputations and well-established, with records of bias against women, the LGBTQ community, people of color, immigrants, environmental protections, and access to health care. They are narrow-minded elitists who favor the wealthy and powerful over the rights of all. None of them would serve as a check on the president.

We already know just how dangerous and consequential one of his previous members of the short list has been. Trump plucked Justice Neil Gorsuch for the Supreme Court seat that Senator Mitch McConnell used unprecedented tactics to hold open long enough for Trump to fill it. This past term, Gorsuch was the fifth and deciding vote to diminish collective bargaining rights, women’s access to health care, fair elections, and access to voting rights.

We cannot let Trump take over the Supreme Court and roll back a century of progress on civil and human rights. This is not a hypothetical threat. It is real. And the more Americans understand the threat that Trump’s shortlisters pose, the better – because our senators need to hear our voices loud and clear.

Senators must put country over party and use all the tools available to them to stop President Trump’s plan to take over the Supreme Court for the next 40 years.

Shin Inouye is director of communications for the Leadership Conference on Civil and Human Rights.