Following the Supreme Court’s landmark Dobbs v. Jackson decision, which overturned Roe v. Wade and returned the power to regulate any aspect of abortion not protected by federal law to individual states, another debate over abortion rights is brewing. At the center of the struggle is a piece of legislation from the 1870s, known as the Comstock Act.

Originally passed in 1873, the law was intended to prohibit the mailing of contraceptives, “lewd” writings and any “instrument, substance, drug, medicine, or thing” that could be used in an abortion. However, over the years federal courts have repeatedly narrowed the Comstock Act’s scope, dropping its reference to contraceptives in the 1970s, while legal experts say the federal government hasn’t even enforced the law since the 1930s.

Yet now, this somewhat forgotten law is receiving renewed attention. Some anti-abortion groups and conservative states are looking to block the mailing of mifepristone, the pill is used in more than half of abortions in the U.S., according to The Associated Press. U.S. District Court Judge Matthew Kacsmaryk has sided with their argument in Texas, putting federal approval of the pill on hold more than two decades after the Food and Drug Administration gave it the initial go ahead.

“We stand by the FDA’s approval of mifepristone, and we are prepared for a long, legal fight.  That’s what I can say from here,” White House press secretary Karine Jean-Pierre said. “That’s what we are committed to do — to doing for the providers who are making sure that this is available to women and also for women out there.”

The judge added the dispensing of “chemical abortion drugs through mail violates unambiguous federal criminal law,” a decision that both the Biden administration and mifepristone’s main drugmaker have filed appeals to challenge. On the same night as that decision, a judge in Washington state ordered the FDA to maintain access to the drug in Democratic-led states that filed their own lawsuit, leaving a pair of dueling opinions that are likely to end up before the Supreme Court.