Democrats in the Senate and House introduced a bill to repeal an archaic law that could be revived to implement a national abortion ban.

Sen. Tina Smith (D-Minn.) introduced the Stop Comstock Act on Thursday afternoon in hopes of repealing the 1873 law that criminalizes sending “obscene” materials in the mail, including anything “intended for producing abortion.” The Comstock Act is not currently being enforced, but Donald Trump’s anti-abortion allies have revealed that they hope to use the law to ban abortion nationwide if the former president is elected again.

If enforced as anti-abortion activists want, the Comstock Act would essentially ban abortion across the country, including in states that currently protect abortion access. It would make it illegal to send abortion pills in the mail ― an avenue that has helped many people access reproductive care in the two years since the U.S. Supreme Court repealed Roe v. Wade. Medication abortions, or abortions using pills, account for more than 60% of abortions in the U.S.

“The Comstock Act is a 150-year-old zombie law banning abortion that’s long been relegated to the dustbin of history,” Smith, who earlier this year wrote an opinion article on her plans to repeal the law, said in a Thursday statement. “But extremist Republicans and Trump judges have seized upon the idea of misusing Comstock to bypass Congress and strip women nationwide of their reproductive freedoms.”

“Now that Trump has overturned Roe, a future Republican administration could try to misapply this 150-year-old Comstock law to deny American women their rights, even in states where abortion rights are protected by state law,” she added. Several Senate Democrats are co-sponsors of the bill, including Elizabeth Warren (Mass.), Catherine Cortez Masto (Nev.) and Sheldon Whitehouse (R.I.).

Rep. Becca Balint (D-Vt.) introduced the House companion bill alongside co-sponsors Cori Bush (D-Mo.), Veronica Escobar (D-Texas), Mary Gay Scanlon (D-Pa.) and Bonnie Watson Coleman (D-N.J.). The bill is endorsed by Planned Parenthood, the American Civil Liberties Union and the Center for Reproductive Rights, among other groups that support abortion rights.

Awareness of the antiquated law is alarmingly low: Two in three Americans do not know about the Comstock Act and its implications, according to recent polling from Navigator Research and Global Strategy Group. Seven in 10 Americans opposed the enforcement of the law after learning about it.

Republicans are betting on the fact that most Americans don’t know about the Comstock Act so that, if elected, Trump could quietly create a backdoor national abortion ban. Jonathan Mitchell, an attorney representing Trump in his immunity case before the Supreme Court, has said that Republicans don’t need a nationwide abortion ban because the Comstock Act exists.

“We don’t need a federal ban when we have Comstock on the books,” Mitchell told The New York Times in February. Mitchell is also the architect of the Texas abortion bounty hunter law, which banned abortion in the state over a year before Roe fell.

He added about Trump: “I hope he doesn’t know about the existence of Comstock, because I just don’t want him to shoot off his mouth. I think the pro-life groups should keep their mouths shut as much as possible until the election.”

“The Comstock Act has long been considered obsolete, but anti-abortion extremists are now threatening to use it to push for a national abortion ban,” Katie O’Connor, director of Federal Abortion Policy at the National Women’s Law Center, said in a statement. “This law, a relic from the 19th century, was originally passed to enforce a specific view of morality rooted in racist, sexist, homophobic, and other discriminatory beliefs. It has no place in our modern laws.”