Judge Kacsmaryk, an appointee of Mr. Trump, is a longtime opponent of abortion and joined the bench after working at First Liberty Institute, a conservative legal group that focuses on issues of religious liberty.
The coalition that brought the suit, the Alliance for Hippocratic Medicine, argued that the F.D.A. had improperly approved the pill in 2000 and that mifepristone is unsafe. The agency has strongly disputed those claims, pointing to studies that show that serious complications are rare and that less than 1 percent of patients need hospitalization.
This month, Judge Kacsmaryk, in a temporary ruling, declared invalid the F.D.A.’s approval of the drug and gave both parties a week to seek emergency relief before the decision took effect.
Less than an hour later, a federal judge in Washington State, Thomas O. Rice, an appointee of President Barack Obama, issued a contradictory ruling in a separate lawsuit over mifepristone. Judge Rice blocked the F.D.A. from limiting the availability of the pill in 17 states and the District of Columbia, which were parties in that suit.
The competing rulings meant that the matter was almost certainly headed to the Supreme Court.
The F.D.A. immediately appealed Judge Kacsmaryk’s decision, and a divided three-judge panel of the Fifth Circuit, in New Orleans, upheld the agency’s approval of the drug, ensuring that mifepristone would remain on the market.
But the panel imposed several barriers to access, siding in part with Judge Kacsmaryk, while the lawsuit moved through the courts. It blocked a series of steps the F.D.A. had taken since 2016 to increase the availability and distribution of the drug, such as allowing it to be sent by mail and to be prescribed by medical providers who are not doctors.
Adam Liptak and Christina Jewett contributed reporting.