A few years ago, I sat in my car outside the tribal clinic on the Wind River Indian Reservation in Wyoming, being tied to my steering wheel by a two-year-old Northern Arapaho boy named Quame. We were waiting for his mother to finish her appointment. Then she and Quame would go home and I would go into the desert with a relative of theirs to look for runaway horses — an adventure I'd been looking forward to for days. But the minutes ticked by without her coming out, and I felt my opportunity f...