Imagine a world where the families of the 23 United States service members killed in the Iran war could sue President Donald Trump for wrongful death, arguing their loved ones died in an illegal war launched without congressional approval. Or where hundreds of wounded veterans pursued negligence claims against Secretary of Defense Pete Hegseth for failing to prepare for the predictable Iranian counterattacks to U.S.-Israeli airstrikes.

This is the reality proposed by “ What a Country Owes Its Soldiers ,” a timely book by Saira Mohamed, a professor at the University of California, Berkeley, School of Law. Across 288 heavily footnoted pages, Ms. Mohamed argues that it is not enough for Americans to fly flags, honor veterans with parades, or even provide generous healthcare, education, and disability benefits. A nation, she writes, owes its soldiers something basic: to be treated as full human beings, who enjoy the same rights as everyone else.

Ms. Mohamed begins her book with a training accident.…