Abortion rights advocates filed a federal lawsuit Tuesday seeking to block a Texas law that would empower private citizens to enforce the state’s ban on virtually all abortions after a fetal heartbeat is detected. 

The 49-page complaint alleges that Texas’s new law, which is set to take effect Sept. 1, runs afoul of a woman’s constitutional right to a pre-viability abortion. It also takes aim at a provision that authorizes citizens to sue those who perform or “aid” abortions after the roughly six-week ban, and provides for at least $10,000 for each successful suit.

“The state has put a bounty on the head of any person or entity who so much as gives a patient money for an abortion after six weeks of pregnancy, before most people know they are pregnant,” Nancy Northup, president of the Center for Reproductive Rights (CRR) said in a statement. “Worse, it will intimidate loved ones from providing support for fear of being sued.”

The lawsuit was filed in federal court in Austin by CRR, Planned Parenthood, the American Civil Liberties Union and others, and seeks to block Texas state judges from enforcing the law and court clerks from accepting lawsuits alleging violations.

The Texas bill at issue, S.B. 8, was signed into law in May by Gov. Greg Abbott (R). It prohibits abortions after the presence of a fetal heartbeat is detected, which can occur as early as six weeks after a woman becomes pregnant, and only makes exceptions for medical emergencies.

Federal courts have blocked similar bills passed in other states, including North Dakota, Iowa, Kentucky and Mississippi.

What sets the Texas bill apart from these, however, is that S.B. 8 prohibits public officials from enforcing the law, in an apparent effort to sidestep legal challenges. Instead, the law deputizes members of the public to sue abortion providers and those who “aid or abet” the procedure after the ban is triggered around six weeks.

“We've never seen a law like this,” Marc Hearron, senior counsel at CRR and the lead attorney on the case, told reporters Tuesday. “This is what Texas politicians wanted when they passed this law: to turn anti-abortion extremists into vigilantes with the power to police clinics, their staff and their patient support systems.”

The Texas measure is among hundreds of abortion restrictions that state legislatures have passed in recent years, some of which pose a direct challenge to the Supreme Court’s landmark 1973 decision in Roe v. Wade. 

The justices are slated to review one such law next term, a Mississippi restriction that bans abortions after 15 weeks, with only narrow exceptions. Supreme Court precedent tracing back to Roe prohibits states from banning abortion before fetal viability, which occurs around 24 weeks.

Abortion rights advocates are warning that dozens of states, particularly in the South and Midwest, are likely to enact severe restrictions and even outright bans on the procedure if the Supreme Court were to overturn Roe v. Wade next term.

--Updated at 1:45 p.m.