Des Moines, Iowa | Every four years since the 1970s, the political gods have smiled upon Iowa, endowing its residents with uncommon power to set the course of national politics as the first nominating contest.

For that privilege, Iowa has found itself — more this year than ever — in the position of defending its perch. Why should a state so disproportionately white take such a leading role, especially for a Democratic Party that prides itself on its diversity? Why is a hodgepodge of gatherings in school gymnasiums the pinnacle of American democracy?