The doctrine has created glaring double standards. After the midair explosion of the space shuttle Challenger, families of civilian crew members were able to file lawsuits against the government, but the family of the pilot, a Navy captain on active duty, could not. Even so, the doctrine has proved durable, surviving five Supreme Court challenges and two previous attempts in Congress to modify it.

“It’s about time” the Feres doctrine was loosened, said Dwight Stirling, a longtime senior prosecutor for the California National Guard who now heads the Center for Law and Military Policy at the University of Southern California. “For too long our troops have been treated like second-class citizens, who serve their country but are denied the rights that everyone else enjoys.”

As a prosecutor, Mr. Stirling said, he saw several victims of sexual assault attempt to seek redress in court, only to have their cases quickly dismissed because both victim and perpetrator were in the military.

“That’s when I started to realize what an injustice the Feres doctrine was,” he said. “It was being used to protect rapists.”

Paradoxically, the Feres doctrine has its legal roots in an effort by Congress to make it easier, not harder, to sue the government. The story started on a foggy morning in 1945, when an Army bomber crashed into the Empire State Building. The accident killed 14 people and injured dozens more, but the victims and their families were unable to sue because of a longstanding legal principle called sovereign immunity, which barred citizens from suing the federal government unless Congress passed a law specifically consenting to the suit.

In the public outcry that followed the crash, Congress passed the 1946 Federal Tort Claims Act, allowing a broad range of civil lawsuits against the government. But it included some exceptions, and one of them was for injuries to troops “arising out of the combatant activities.”