All presidencies are historic. But no president since at least LBJ, and probably FDR, has arrived in Washington at a moment of greater historic urgency than Barack Obama. The man who took that oath of office seemed cut from American folklore — a neophyte politician elected senator only four years before, a prodigious and preacherly orator from the “Land of Lincoln” and the South Side of Chicago of the Great Migration. An embodiment not just of the American Dream as it had been imagined by the Greatest Generation of his own maternal grandparents but of a new version, too, one that might be embraced by his daughters — global, utopian-ish, post-boomer, “post-racial.”

More than “hope,” Obama’s candidacy promised “one America.” It is the deep irony of his presidency, and for Obama himself probably the tragedy, that the past eight years saw the country fiercely divided against itself. The president still managed to get a ridiculous amount done, advancing an unusually progressive agenda. But however Americans end up remembering the Obama years decades from now, one thing we can say for sure is that it did not feel, at the time, like an unmitigated liberal triumph. It felt like a cold civil war.

Or a never-breaking political fever. There was the tea-party rage and Occupy Wall Street. Every other week, it seemed, a new shooting. Each movement was met by a countermovement, and yet, somehow, both the left and the right were invigorated, watched over by a president marked so deeply by temperamental centrism even his supporters called him Spock. Whether you noticed or not, our culture was shaken to its core. There was a whole new civil-rights era, both for those whose skin color and for those whose love was long met by prejudice. The first iPhone was released during the 2008 campaign. We got our news from Facebook, debated consent, and took down Bill Cosby. Elon Musk built a spaceship to Mars.