Under the law, private citizens can bring state court litigation against clinics or anyone else who facilitates an abortion after fetal cardiac activity is detected -- a point about six weeks into pregnancy and often before a woman knows she is pregnant.

The law provides no exception for rape or incest, although there is an exemption for "medical emergencies."

In its brief, the Justice Department shot back at Texas' claim that Pitman had erred in targeting his order at state court officials, among others.

"Having chosen this supremely unusual means of enforcing its unconstitutional law, Texas bears the obligation to identify an alternative form of injunctive relief if it is dissatisfied with the particular mechanism adopted by the district court.

Tellingly, Texas has not done so," the department said.