GEOFF BENNETT: Access to medication abortion faced a critical test today in the conservative Fifth Circuit Court of Appeals.

A three-judge panel of Republican appointees heard arguments about whether the abortion pill mifepristone, first approved by the FDA more than 20 years ago, should stay on the market.

It's the latest legal battle since the Supreme Court overturned Roe v. Wade last year.

Joining us with reporting and analysis, Sarah Varney, a correspondent for KFF Health News who has been reporting for the "NewsHour" about abortion access since the overturning of Roe, and Steve Vladeck, professor at the University of Texas School of Law and an expert on federal courts.

His new book on the Supreme Court is "The Shadow Docket."

Thank you both for being with us.

And, Sarah, we will start with you.

Remind us why this case is so significant, said to be the most consequential since the overturning of Roe.

SARAH VARNEY, KFF Health News: In the last number of years, the number of women who rely on medication abortion pills has grown to more than 50 percent.

So access to this medication abortion regimen is incredibly important for women around the country.

So, when Judge Kacsmaryk issued his decision in Texas, before it was stayed, it essentially said that mifepristone would have to come off the market.

So that would affect, of course, women who want to access abortion medication to terminate a pregnancy.

It's also used a lot in early miscarriage management treatment.

So that's something that physicians, OB-GYN around the country regularly turn to.

GEOFF BENNETT: And, Steve, the New Orleans-based Fifth Circuit is considered one of the most conservative appellate courts in the country.

They have routinely ruled against the Biden DOJ.

What lines of inquiry did the judges explore today?

And what can you glean from it?

STEPHEN VLADECK, University of Texas School of Law: Yes, I mean, there's a lot of talk drawn to this argument about standing, this technical legal doctrine, which is basically asking, are these the right plaintiffs to be challenging the FDA's 2000 and subsequent approvals of mifepristone?

I think what we heard from all three of the judges on the panel, all three of whom were Republican appointees, was real efforts to bolster, to support Judge Kacsmaryk's analysis of why these doctors could challenge the FDA's actions, Geoff, even though in most of the -- almost all of these contexts, the doctors are claiming an injury based upon something that may or may not happen in the future, which is that patients who have taken mifepristone will need some kind of for emergency or urgent care.

That's not usually enough for standing under the Supreme Court's precedents.

Indeed, that kind of hostility to standing has been a staple of conservative jurisprudence for most of the last 50 years.

GEOFF BENNETT: Yes.

And so this is likely going to head back to the Supreme Court.

The fact that the court preserved access to mifepristone while this appeal was making its way through the system, what does that suggest?

STEPHEN VLADECK: Yes, it's a little tricky, because the Supreme Court's ruling from April had no analysis with it.

So we don't know why a majority of the justices voted to keep Kacsmaryk's ruling on hold.

Geoff, we don't even know how many voted.

We just know it was five or more.

But I do think it's a pretty good sign that at least five of the justices are likely to reverse, to be unsympathetic to Judge Kacsmaryk, whether because they don't think the plaintiffs have standing, or because they're willing to side with the Biden administration on the merits.

What's so important for now is that nothing the Fifth Circuit decides is going to affect the status quo.

The stay the Supreme Court issued preserving nationwide access will remain in place until the Supreme Court acts, regardless of what the court of appeals does.

GEOFF BENNETT: And, Sarah, you have talked to abortion providers, women health experts and advocates.

How do they see this moment?

SARAH VARNEY: Well, I think they're very relieved that mifepristone will remain on the market while this case plays out, which could take months, if not years, to reach the Supreme Court.

This is -- as we were discussing, it's just really about the stay of Judge Kacsmaryk's order.

So there's a whole other trial that can happen to sort of discuss the merits of this case.

One of the things we actually heard from one of the judges today was, can we basically get the file from the FDA, the sort of full file going back to 2000?

And the Justice Department has not been able to produce that yet, in part, she said, because this is a quarter-century old, and we have to go back into, she said, deep storage to literally pull out the entire file about mifepristone.

So this case could take many, many months, if not years, to resolve itself.

GEOFF BENNETT: Steve, on the specific question of safety, we know that mifepristone sends fewer people to the E.R.

than Tylenol and Viagra.

So, if this case is successful, if the court effectively bans access to mifepristone, what does that mean for the FDA's regulatory authority over other drugs?

STEPHEN VLADECK: I think it means it's open season, and that we're going to see challenges, whether it's from the left, from the right, from the sort of anti-science part of the community to a wide range of FDA approvals, both old ones and new ones, from over-the-counter medicines, to vaccines, to every kind of experimental treatment you can think of.

It will essentially be the Wild West.

And I think that's part of why we saw the U.S. Supreme Court step in, not because the conservative justices are especially sympathetic to the nationwide availability of mifepristone, but because I think they can see, at least some of them can see the writing on the wall in a world in which 23 years after the FDA approves a medication, anyone can walk into a handpicked federal courthouse and get a federal judge to second-guess that decision.

GEOFF BENNETT: And when you say handpicked federal courthouse, you mean the fact that they -- this case was filed specifically in Texas because they knew that it would end up before the specific appellate court.

STEPHEN VLADECK: That's right, so not just in Texas, but by filing in Amarillo, the Amarillo Division of the Northern District of Texas, the plaintiffs, the Alliance for Hippocratic Medicine, Geoff, they had a 100 percent chance of having the case be assigned to this specific judge, Judge Matthew Kacsmaryk, who is pretty well-known as an anti-abortion advocate before he went on the federal bench.

Folks are going to have their own views about whether that's a healthy practice or not.

When anyone can take advantage of that kind of manipulation of the trial court system, that's part of why this has such potentially cataclysmic implications for the entire universe of medication, of drug safety approval, because now you're going to see copycat lawsuits that have nothing to do with abortion where you don't even have the same political valence and where it's just everything that the FDA has done becomes open to challenge.

GEOFF BENNETT: And, Sarah, you have been following this since the very beginning.

What are you watching for as this case unfolds?

SARAH VARNEY: Well, I think this question of standing is very interesting.

I mean, I agree that it sounds like the justices at the court today were really trying to allow the anti-abortion groups to gain some credibility in their standing question.

The other thing I thought was really interesting today was Judge James Ho, who is a Trump appointee, he kept saying several times, seems that your argument is that the FDA can do no wrong.

And he recited several other drugs that had been removed from the marketplace.

The Justice Department attorney came back and said, well, that was because the FDA went through a review process and removed the drug.

But there does -- did seem to be some hostility from Judge Ho about this idea that we should leave these decisions up to scientific and medical experts at the FDA.

The other thing I thought was interesting was just this big question about doctors practicing medicine.

And you saw several the judges ask about, well, shouldn't doctors have to use an ultrasound?

Shouldn't they have to see a patient in person?

And the Justice Department would come back and say, we ask doctors to practice medicine.

In fact, you can ask a woman a lot of questions to determine whether or not she has an ectopic pregnancy, if there's referred pain in her shoulder, for instance, and that these things are very predictive of an ectopic pregnancy, or when was your last period?

That can give us a real sense, of course, of how far along into a pregnancy is somebody.

And you heard, I thought, from the judges, at least, this real interest in not believing doctors, not really trusting doctors to suss that out for themselves.

So that's what I will be looking for as well.

GEOFF BENNETT: You were shaking your head in agreement about the question of not trusting doctors.

STEPHEN VLADECK: Yes, I mean, I think, Geoff, at the end of the day, the question is, who do we think is in a better position to measure, to weigh the medical the scientific evidence, the folks at the FDA, who are appointed by the president, who are given those positions because they have those qualifications, or federal judges, right?

No one's really arguing that the government's actions are totally unreviewable.

But when you have a system where a single federal judge anywhere in the country is in a position to just brush to the side 23 years of scientific medical evidence that the agency Congress has created to answer those questions has compiled, I think you see why this has potentially such enormous ramifications, far beyond even the enormous mifepristone-specific ramifications of this one case.

GEOFF BENNETT: Steve Vladeck and Sarah Varney, thank you both for your analysis and your reporting.

Appreciate it.

STEPHEN VLADECK: Thank you.