Nineteenth-century grass-roots populism made twentieth-century progressivism possible.

My mother married my father in 1956. She was twenty-eight, and he was thirty-one. She loved him with a fierce steadiness borne of loyalty, determination, and an unyielding dignity.

Germ theory, which secularized infectious disease, had a side effect: it sacralized epidemiology.

A great deal of what many Americans hold dear is nowhere written on those four pages of parchment, or in any of the amendments. What has made the Constitution durable is the same as what makes it demanding: the fact that so much was left out.

History is the art of making an argument about the past by telling a story accountable to evidence. In the writing of history, a story without an argument fades into antiquarianism; an argument without a story risks pedantry. Writing history requires empathy, inquiry, and debate. It requires forswearing condescension, cant, and nostalgia. The past isn’t quaint. Much of it, in fact, is bleak.

Old reference books are like tree rings. Without them, there'd be no way to know what a tree had lived through.

Republicans were more pro-choice than Democrats up until the late 1980s.