Saying the law is “plainly unconstitutional,” the department also asked the court to add the case to its docket in its current term.

WASHINGTON — In a forceful brief filed Monday, the Biden administration urged the Supreme Court to temporarily block a Texas law that bans most abortions in the state while a legal challenge moves forward, calling the law “plainly unconstitutional.”.

Leaving the law in effect, the brief said, would allow Texas to flout half a century of Supreme Court precedents that forbid states from banning abortions before fetal viability, or about 22 to 24 weeks into a pregnancy.

Alito Jr., who oversees the federal appeals court responsible for Texas, asked officials there to file their response to the Justice Department’s application by Thursday at noon.

Saying the matter was urgent and important, the brief also asked the court to consider adding the question of the law’s constitutionality to the docket of cases it plans to hear this year, bypassing the appeals court, which is scheduled to hear arguments on it in December.

The Supreme Court is already scheduled to hear another major abortion case, involving a Mississippi law, in December.

In a bitterly divided decision last month in a different case, one brought by abortion providers regarding the same law, the Supreme Court let the law go into effect, effectively ending access to abortion for most Texas women.

Late last month, the providers asked the court to take another look at the case and to put their request on an unusually fast track.

The Texas law, which has no exception for pregnancies resulting from rape or incest, has an unusual feature that has complicated efforts to challenge it in court.

The law’s defenders say that providers can challenge the law by violating it, getting sued and asserting the law’s unconstitutionality as part of their defense.

The application filed Monday asked the Supreme Court to lift the stay.

The majority opinion in last month’s 5-to-4 Supreme Court decision refusing to block the law was unsigned and consisted of a single long paragraph.

It said the abortion providers who had challenged the law in an emergency application to the court had not made their case in the face of “complex and novel” procedural questions.

Fletcher wrote, noting that both laws would contravene Supreme Court precedents