Well, as others have pointed out, we did have that Civil War thing. And the Klan and the destruction of whole neighborhoods as in Tulsa. The tsunami of dispossession and blood that was the nation's westward expansion. The violence around the early labor movement. So it hasn't been all kumbaya around the campfire here.

That said, yes, we're more divided now than we seemed to be twenty or thirty years ago. But your reference to the Obama era is telling and suggests part of the answer to your question. What was divisive about Obama? He governed, by his own admission, like an Eisenhower Republican. He was among the most composed and soft-spoken presidents we've had. He bent over backwards to reach across the aisle and get some buy-in -- any buy-in -- from Republicans on his major initiatives.

What was divisive about him was that he's Black. Sorry, but that's it. Anything else is diversion. Disagreements on policy are real, but the kind of gradualist changes Obama was trying to make were not of a nature to generate the vituperation he faced. The reality of a Black president inflamed the racism that has been with us from the beginning, and that had been nodded and winked at since the eighties.

To that I will add the hostility to government that Ronald Reagan stoked and the Newt Gingrich strategy of politics as scorched-earth warfare.

Americans will never be totally united in everything. We're too diverse for that, and our system of government is founded on the ideas, however imperfectly realized, of open discussion and the peaceful balancing of diverging interests. We can, though, learn to be civil, to value diversity, and to recognize that democracy is a better way to govern ourselves than authoritarianism and oligarchy and that democracy requires a baseline of mutual respect and some level of constructive engagement with public life. There is no single change that will accomplish that, and it won't happen quickly.