I figured the mark, distinguishable only by another believer, was a foolproof test of who was with us and who wasn’t. What do we do now—try the smudge test on anybody who’s bearing the mark?” “Nope,” T said. “Don’t have to.” “Why’s that?” “You’re not testing my mark, are you? Why do you assume I’m legit?” “Because you weren’t attacked.” “Bingo. For the next ten months, that is our litmus test.”