FORT RILEY, Kan. — When Specialist Jeremy Hall held a meeting last July for atheists and freethinkers at Camp Speicher in Iraq, he was excited, he said, to see an officer attending. But minutes into the talk, the officer, Maj. Freddy J. Welborn, began to berate Specialist Hall and another soldier about atheism, Specialist Hall wrote in a sworn statement. “People like you are not holding up the Constitution and are going against what the founding fathers, who were Christians, wanted for America!” Major Welborn said, according to the statement. Major Welborn told the soldiers he might bar them from...