AUSTIN (Nexstar) — A federal judge heard arguments Friday over whether Texas can leave in place the nation’s most restrictive abortion law, which has banned most abortions and sent women racing to get care beyond the borders of the second-most populous state in the U.S.

That law is now in the hands of U.S. District Judge Robert Pitman, an appointee of former President Barack Obama, who questioned the private enforcement aspect of the law in court Friday. Pitman gave subtle signals how he might rule, at one point questioning Texas lawmakers’ unique approach of relying on private citizens to enforce the ban, not the state.

“I guess my obvious question to you is if the state is so confident in the constitutionality of the limitations on women’s access to abortion, then why did you go to such great lengths to create this very unusual private cause of action rather than just simply doing it directly?” Pitman asked the state’s defense.

The U.S. Department of Justice sued Texas Sept. 9 for its abortion law that went into effect Sept. 1, in an attempt to block it from being enforced. Despite this, Senate Bill 8 still stands in Texas, banning abortions once a “fetal heartbeat” is detected. The law describes “fetal heartbeat” as “cardiac activity,” which can be detected as early as six weeks — a time when many women do not know they are pregnant.

The lawsuit seeks to land the first legal blow against the state law that has thus far withstood an early wave of challenges, including one reviewed by the U.S. Supreme Court, which allowed it to remain in place.

The law also makes no exceptions in cases of rape or incest. Private citizens are entitled to at least $10,000 in damages if they are successful in suing not just abortion providers who violate the law, but anyone found to have helped a woman get an abortion. The patient who received the abortion cannot be sued.

“A state may not ban abortions at six weeks. Texas knew this, but it wanted a six-week ban anyway, so the state resorted to an unprecedented scheme of vigilante justice that was designed to scare abortion providers and others who might help women exercise their constitutional rights,” Justice Department attorney Brian Netter told the court.

Since the law took effect, abortion providers say, “exactly what we feared” has become reality. They have described Texas clinics that are now in danger of closing while neighboring states struggle to keep up with a surge of patients who must drive hundreds of miles from Texas. Other women, they say, are being forced to carry pregnancies to term.

“This is not some kind of vigilante scheme,” said Will Thompson, defending the law for the Texas Attorney General’s Office. “This is a scheme that uses the normal, lawful process of justice in Texas.”

Thompson argued the federal government cannot sue the state, in part, because its not up to the state to enforce the law. Meaning, there would be no state officials or entities that could be subject to a court order blocking the ban. Because of that argument, Pitman asked Thompson who he would identify as the proper defendants or objects of an injunction would be.

“There is no public official who enforces the Texas Heartbeat Act,” Thompson said. “…so I don’t think there is someone I can identify for the court, because I don’t think any such person exists.”

The state also argued the DOJ doesn’t have a cause of action, since abortions are not a specifically protected right under the U.S. Constitution.

When announcing the lawsuit in September, U.S. Attorney General Merrick Garland said Texas’ law is “clearly unconstitutional” under the long-standing precedent established by Roe v. Wade, in which the High Court found the Constitution protects a woman’s liberty to choose to have an abortion, without excessive government restriction.

“Those precedents hold, in the words of Planned Parenthood v. Casey, that ‘regardless of whether exceptions are made for particular circumstances, a state may not prohibit any woman from making the ultimate decision to terminate her pregnancy before viability,'” Garland said.

It is unclear how soon Pitman will decide.

It is also unclear how quickly any of Texas’ nearly two dozen abortion clinics would move to resume normal operations if the law is set aside. Texas officials would likely seek a swift reversal from the 5th U.S. Circuit Court of Appeals, which previously allowed the restrictions to take effect.

“Abortion care has almost completely stopped in our state,” Dr. Ghazaleh Moayedi, a Texas abortion provider, told the U.S. House Oversight and Reform Committee during a hearing over abortion access Thursday.

The Texas law is just one that has set up the biggest test of abortion rights in the U.S. in decades, and it is part of a broader push by Republicans nationwide to impose new restrictions on abortion.