It was a scorching hot afternoon here in California when I picked up my cellphone and dialed the unfamiliar number. On the other end, a gruff but friendly voice answered, his Hmong accent thick but still had a touch of central-California mixed in, a throw-back to the state where he’d grown up. He’d been expecting my call, and though this was the first time we’d ever talked, he was warm and easily opened up. Under...