The Biden administration sued Texas on Thursday to try to block the nation’s most restrictive abortion law, which bans the procedure as early as six weeks into pregnancy and allows private citizens to take legal action against anyone who helps a woman terminate her pregnancy.

The law took effect Sept. 1, effectively ending most abortions in the nation’s second-most-populous state, with no exceptions for rape or incest.

The suit filed by the Justice Department in federal court in Austin asks a judge to “protect the rights that Texas has violated” by declaring the abortion law unconstitutional and issuing an injunction blocking its enforcement. At a news conference, Attorney General Merrick Garland said the ban “is clearly unconstitutional under long-standing Supreme Court precedent.”

“This kind of scheme to nullify the Constitution of the United States is one that all Americans, whatever their politics or party, should fear,” said Garland, warning that what he called the “bounty hunter” element of the law may become “a model for action in other areas by other states and with respect to other constitutional rights or judicial precedents.” The U.S. government, Garland added, has a responsibility “to ensure that no state can deprive individuals of their constitutional rights.”

A spokeswoman for Texas Gov. Greg Abbott (R) defended the law and accused the Biden administration of acting for political reasons — to distract Americans from the U.S. withdrawal from Afghanistan and the influx of migrants at the U.S.-Mexico border.

“We are confident that the courts will uphold and protect that right to life,” press secretary Renae Eze said in a statement.

The case has been assigned to District Court Judge Robert L. Pitman, who is already deeply familiar with the law: he is also presiding over a separate pending legal challenge to the abortion ban brought by a coalition of abortion providers and advocates.

In that case, Pitman had scheduled a hearing to consider whether to block enforcement of the ban before it took effect. But the conservative U.S. Court of Appeals for the 5th Circuit called off the hearing.

On Friday, the appeals court issued a new order saying it would hear a preliminary appeal of that earlier case on an expedited basis. The 5th Circuit's initial action led to an emergency petition to the Supreme Court, which decided 5-4 to allow the Texas law to stand while the litigation continues.

The Biden administration’s suit argues that the Texas law violates the 14th Amendment’s due process clause, saying the measure deprives women in Texas of the right to an abortion and imposes an “undue burden” — and that the Constitution generally takes precedence over state laws.

The suit also says the measure interferes with the federal government’s constitutional obligation to provide access to abortion, including in cases of rape or incest, to people in the custody or care of federal agencies or government contractors, including at prisons.

President Biden and Democrats in Congress have criticized the Texas law and the initial refusal of the high court to block the ban.

Any action Pitman takes in response to the lawsuit is likely to be appealed to the 5th Circuit and, eventually, to return to the high court.

A dozen other states have passed legislation banning abortions after about six weeks into pregnancy. But federal judges have stopped those measures from taking effect, finding the laws inconsistent with Roe v. Wade, the 1973 Supreme Court decision guaranteeing the right to choose abortion before viability, usually around 22 to 24 weeks.

The Texas law was designed to withstand a similar preemptive legal challenge. It intentionally bars enforcement by state government officials, whom abortion providers would typically target in a lawsuit. Instead, the law empowers private citizens to file civil lawsuits against anyone who helps a woman get an abortion after the six-week window. Individuals can receive a $10,000 award if their lawsuits are successful. They can sue abortion providers, clinic workers or those who help a woman pay for the procedure or drive her to a clinic.

In its 5-to-4 decision last week, the Supreme Court’s conservative majority said abortion providers and civil rights groups had “raised serious questions regarding the constitutionality of the Texas law.” But the court allowed the ban to take effect while the legal battle plays out, saying the abortion providers and advocates who had challenged the law could not show they were suing the right people.

Their lawsuit targeted state court judges and court clerks, who would have to accept lawsuits alleging violations of the ban for those suits to go forward. The majority said it was premature for the court to step in because it is “unclear whether the named defendants can or will seek to enforce the Texas law.”

All of the dissenting justices wrote separately, with the court’s three liberal justices characterizing the Texas law as an end run around the Constitution and court precedent.

Garland said Monday that his agency would do all it could to guarantee access to abortion in Texas. But advocates said the pledge lacked specifics; they urged a direct challenge.

Asked Thursday about the intense pressure from Democrats to take action, Garland said the department “does not file lawsuits based on pressure. We carefully evaluated the law and the facts, and this complaint expresses our view of the law and the facts.”

The lawsuit seeks to stop not only the state but also private individuals who would bring civil lawsuits to enforce the Texas law.

In response, Texas Attorney General Ken Paxton (R) tweeted, “Today the Biden Administration sued every individual in Texas” and said Biden should not meddle in a state’s “sovereign rights.”

Steve Vladeck, a constitutional law professor at the University of Texas law school, called the lawsuit “an ambitious and powerful” effort “to protect the constitutional rights of citizens.” The question, he said, is whether citizens who try to enforce the law are “agents of the state and therefore subject to the injunction the government is seeking.”

“That’s a very broad request for relief,” said Vladeck, who has been publicly critical of the way the law was designed to avoid judicial review, “but also perhaps necessary given the novel and cynical procedural traps Texas created.”

Supporters of the law put out a statement criticizing the federal lawsuit even before Garland’s news conference. They called the suit a “desperate attempt” to block the measure.

Biden “is a puppet of the radical abortion agenda, and his DOJ will quickly find that they do not have jurisdiction to stop the Texas Heartbeat Act,” said Elizabeth Graham, vice president of Texas Right to Life.

The law is already having an effect. Abortion clinics in Texas say they are abiding by the six-week ban and sending women who are further along in their pregnancies across state lines to seek the procedure.

Texas Right to Life, which backed the law, was collecting anonymous tips on its website about potential violations of the law, but so far no lawsuits have been filed against abortion providers in state court.

If such a lawsuit is filed, it would almost certainly be challenged, creating a new path for the constitutionality of the abortion ban to be reviewed by the courts.

Several advocacy organizations that help women access abortions already have won temporary restraining orders in local courts that bar Texas Right to Life and others from using the law to sue them.

But those court orders are limited to the people involved and do not stop other individuals or organizations from filing lawsuits against anyone involved in an abortion banned under the Texas law.