The 3-month-old baby in the airplane had a scabby forehead and dirty fingernails, yet she was a dark-eyed darling in her father’s arms. She was named after her dead mother, Maria Isabella, and she had spent her life to that point traveling north from El Salvador. All she knew was her family’s passage to the U.S. border. She waggled her head back and forth when she cried. Her father’s name was Santo—“Saint”—and he had suffered enough to be one. He had taken his four children more than a thousand miles north with only a purse-sized travel bag. In El Salvador, he was a thick-handed, hard-nailed field worker who turned maize into tortillas. He planned to work in a laundromat. It would be better for his children there, he said. He didn’t know how to buckle or unbuckle an airplane seatbelt. He didn’t know how to navigate an airport. “La vida …