The lawyers’ focus on 150 miles has to do with a federal appeals court decision that found that driving distances of up to 150 miles and up to three hours do not qualify as an undue burden. As a result, the precise distances and affected populations have been a focus of much of the case. Each side hired its own experts and researchers to analyze the travel distances and called them to the stand, and maps of Texas with 150-mile zones circled in red were displayed in the courtroom.

Lawyers for the plaintiffs have been newly optimistic about their chances of striking down parts of the law. Last month, a federal appeals panel, in a Mississippi case with similarities to the one in Texas, ruled that Mississippi officials could not rely on out-of-state clinics in claiming their abortion regulations were constitutional.

“I think it’s a really important decision, and I think it undercuts what the state’s arguing about sending women to New Mexico,” said Jan Soifer, one of the lawyers for the clinics suing the state. “In a state this large with this many women, for the state to say, ‘Well, it’s O.K., you can cross the border and go to a clinic in another state,’ is the state shirking its requirements to ensure that the constitutional rights of the women in the state are met.”

Lawyers for the Texas attorney general, Greg Abbott, defended the law as constitutional and not unduly burdensome, whether the New Mexico clinic was included or excluded. “It would be safer for patients to drive further to receive an abortion at a surgical facility with a credentialed and privileged physician than to seek an abortion at a nearby, substandard clinic,” the lawyers wrote in court documents.

Nevertheless, the status of the clinic in New Mexico has raised concerns. The clinic, Hilltop Women’s Reproductive Clinic, lists a license number on its website. A spokesman for the New Mexico Department of Health, Kenny Vigil, said that the department has not licensed the Hilltop clinic and that the license number listed on the website “is not a license number issued by the New Mexico Department of Health.”

Abortion clinics in New Mexico are not required to be licensed by the state health department and can seek other forms of accreditation. The owner of the Hilltop clinic, Dr. Franz Theard, has an active physician’s license from the New Mexico Medical Board. He did not respond to requests for comment.

Ms. Soifer, the lawyer for the Texas abortion clinics, said the issue highlighted the plaintiffs’ arguments that Texas does not know whether New Mexico’s abortion providers will provide safe services.