AMARILLO, Texas (AP) — A conservative judge in Texas raised questions Wednesday about a Christian group's effort to overturn federal regulators' decades-old approval of a leading abortion drug, in a case that could threaten the country's most common method to end pregnancies.

Judge Matthew Kacsmaryk heard more than four hours of debate over the Alliance Defending Freedom's request to revoke or suspend the Food and Drug Administration’s approval of mifepristone. Such a step would be an unprecedented challenge to the FDA and its authority in deciding which drugs to permit on the market.

Kacsmaryk said he would rule “as soon as possible,” without giving any clear indication of how he might decide and leaving open the question of whether access to the standard regimen for medication abortions might soon be curtailed throughout the country.

Mifepristone, when combined with a second pill, was approved in 2000 and is used to end pregnancies until their 10th week. It has been increasingly prescribed since last summer’s U.S. Supreme Court ruling overturning Roe v. Wade.

The Texas lawsuit has become the latest high-stakes legal battle over access to abortion since the question of its legality was returned to the states.

Kacsmaryk, who was appointed by former president Donald Trump, saved some of his most pointed questions for attorneys representing the alliance, which filed the case in Amarillo in anticipation of getting a favorable ruling.

“Explain to me why this court has that sweeping authority?” Kacsmaryk asked, in reference to the group's request to pull mifepristone from the market.

The judge also questioned whether the group had the legal standing to obtain a pretrial ruling, grilling both sides on U.S. Supreme Court cases that set out when such extraordinary relief is allowed.

Still, the judge also posed questions suggesting he was considering how he might draft a preliminary injunction in the plaintiffs' favor, at one point asking the alliance's lawyers if the issue of standing had been clearly addressed by appellate courts. At another point, he told them that their outline for the order of their arguments “tracks the elements for an injunction nicely.”

Lawyers representing the FDA argued that pulling mifepristone would disrupt reproductive care for American women across the U.S.

“An injunction here would interfere with the interests of every state in the country” said Julie Harris of the U.S. Justice Department, which represented the FDA.

Harris and her colleagues also questioned whether the Alliance — which filed its case on behalf of several anti-abortion doctors — had standing to bring the lawsuit, given that none could show the type of harm typically needed to request legal action.

One of the chief arguments leveled against the FDA in the lawsuit is that the agency misused its authority when it originally approved the abortion pill.

The FDA reviewed the drug under its so-called accelerated approval program, which was created in the early 1990s to speed access to the first HIV drugs. Since then, it has been used to expedite drugs for cancer and other “serious or life-threatening diseases."

“The plain text is clear it applies to illnesses,” argued Erik Baptist, the alliance's lead attorney. “Mifepristone is used to end pregnancies, and pregnancy isn’t an illness.”

The FDA rejected the group’s argument on multiple accounts. First, attorneys said FDA regulations make clear that pregnancy is considered a “medical condition” that can be serious and life-threatening in some cases.

Second, government attorneys said the terms of mifepristone’s approval were replaced more than a decade ago by subsequent FDA programs passed by Congress, rendering the argument irrelevant.

Finally, while the FDA reviewed the drug under its accelerated approval regime, it didn’t expedite the drug’s review. In fact, approval only came after four years of deliberation. Instead, the FDA used regulatory powers under the accelerated program to add extra safety restrictions to mifepristone.

Legal experts have long been deeply skeptical of many of the arguments made in the alliance’s lawsuit. And there is essentially no precedent for a lone judge overruling the scientific judgments of the FDA

At one point, Kacsmaryk asked the alliance's attorneys about the possibility of suspending mifepristone's approval, without withdrawing it completely.

“Any relief you grant must be complete” and apply nationwide, Baptist responded. “The harms of these abortion drugs know no bounds.”

Kacsmaryk gave each side two hours to make their arguments — with time for rebuttal — in the high-stakes case. Mifepristone’s manufacturer, Danco Laboratories, joined the FDA in arguing to keep the pill available.

A ruling could come any time. A decision against the drug would be swiftly appealed by U.S. Department of Justice attorneys representing the FDA, who would also likely seek an emergency stay to stop it from taking effect while the case proceeds.

Members of the Women’s March advocacy group rallied outside the courthouse, including one dressed as a kangaroo to decry the proceedings as a “kangaroo court.”

Ultimately, courthouse officials allowed 20 members of the media and 20 members of the general public to attend the hearing. Most of the benches were full, though two rows of seating designated for courthouse staff and attorneys were not.

If Kacsmaryk rules against the FDA, it’s unclear how quickly access to mifepristone could be curtailed or how the process would work. The FDA has its own procedures for revoking drug approvals that involve public hearings and scientific deliberations, which can take months or years.

If mifepristone is sidelined, clinics and doctors that prescribe the combination say they would switch to using only misoprostol, the other drug used in the two-drug combination. That single-drug approach has a slightly lower rate of effectiveness in ending pregnancies but is widely used in countries where mifepristone is illegal or unavailable.

In addition to challenging mifepristone's approval process, the lawsuit takes aim at several later FDA decisions that loosened restrictions on the pill, including eliminating a requirement that women pick it up in person.