The prairie reveals. Any hilltop’s field of vision opens to evidence of energy and motion, fresh tracks, today mostly tire tracks of the present, but also old tracks through time. I have come to North Dakota to single out a particular and peculiar set of tracks — hoofprints, really — for what they tell us about our destruction of the natural world.

Theodore Roosevelt arrived in the town of Little Missouri, in the center of the Dakota Territory, in 1883, in his early twenties, then all buckskin, bluster, teeth, and glasses. He came first of all to kill animals and then to write about it. But Roosevelt was already an accomplished naturalist and convinced Darwinist, and he came also to see the raw nature then on display in the Badlands, a stark landscape of eroded clay and red scoria in the southwest corner of what is now North Dakota, a bit of geologic chaos that serves as counterpoint to the gentle prairie all around.

The year that followed was disastrous for Roosevelt. On Valentine’s Day 1884, his mother, Mittie, and his young blue-blood wife, Alice Lee, herself recently a mother, died in the same house on West 57th Street in Manhattan. That summer, at the Republican National Convention in Chicago, he suffered a professional setback to go with his personal catastrophe when his preferred candidate was kept off the ticket. Instead of heading home from the convention, Roosevelt took a train straight from Chicago back to the Badlands, this time intending to stay a while. He bought a ranch, which he named the Elkhorn. Roosevelt wrote volumes about the Badlands, but never about what settled his grief while he was there. In any case, when he returned to New York and to politics, in 1886, he was transformed.

Before heading west, Roosevelt had already made a name for himself as viscerally and implacably opposed to corruption, taking on Tammany Hall in the New York legislature, laying the foundation of what would become a career of trust-busting that closed the Gilded Age and eventually broke up John D. Rockefeller’s megamonopoly, Standard Oil. But at the Elkhorn he learned a deep engagement with the landscape, a love of the wild, and he reinforced an obsession with the strenuous that would take him through life. His character formed. What happened there propelled Roosevelt almost single-handedly to found the American conservation movement, leading one Roosevelt scholar to call the Elkhorn the “cradle of conservation.”