I hope you've all had a happy and relaxing Thanksgiving. I was lucky to host this year, with both my wife's family and mine traveling here to scenic Ohio, and I was also the lucky cook. (I took over turkey and gravy a few years ago, but this was my first year doing the whole meal, and -- since people had traveled to see us -- also feeding the crew on Tuesday and Wednesday nights.) And I was lucky enough to avoid political arguments at the table, because no one in my family voted for Trump. But political arguments on Thanksgiving are not the end of the world. Thanksgiving, as a national holiday, is the direct result of political conflict, and it's a mistake for us to forget that.

So, a quick history lesson:

Everybody knows the story about the first Thanksgiving at Plymouth Plantation. And that's true, in the sense that the event really did take place. But that's not when Thanksgiving became a national or even a regular holiday. The Pilgrims didn't have another Thanksgiving the next November. And some people know the historical fact that Lincoln proclaimed the first regular, national Thanksgiving, although that fact tends to confuse people. How did this holiday get founded twice, first in 1621 and then in 1863? And how can it be that Thanksgiving's two original moments happen more than 240 years apart?

A quick google search will explain that Lincoln simply set a standard national date for Thanksgiving, which different states were celebrating on different days. And that is part of the story. But that makes it sound as if the whole country was already united behind Thanksgiving, which only the logistical problem of deciding when to have it. That's not true. (Think "things left to the states to decide" and "Lincoln" and you'll see where this story is going.)

The real truth is that Thanksgiving was originally part of America's cultural wars, and so was Christmas. We now think of those two holidays as part of a single season, but they used to be indirectly (and sometimes pretty directly) opposed to each other. Not everyone celebrated both, and the division between the holidays broke down on regional, religious, and ideological lines.

Thanksgiving is a New England thing. It was originally a regional holiday, celebrated by New Englanders. It's also, not to put too fine a point on it, a Puritan holiday, celebrated in the Northeast by Congregationalists, Presbyterians, and other churches with Puritan roots. Thanksgiving was especially valuable to these Puritan-leaning New Englanders because they did not celebrate Christmas. They actively despised Christmas as a lot of heathenish nonsense. Celebrating it, or even closing the store on December 25, went against their religious beliefs.

On the other hand, Christmas was widely celebrated in the South, which had been heavily settled by Anglicans who observed the traditional liturgical holidays. (New York was also a stronghold of Christmas, partly because of its old Dutch roots and partly because it was such an ethnic and religious melting pot.) But plenty of Southerners wanted nothing to do with Thanksgiving. They saw it as alien: a celebration of another region's culture and another denomination's beliefs. They were not wrong. A lot of Southerners also saw Thanksgiving as an abolitionist thing, and they weren't wrong about that either. The lead campaigner for Thanksgiving as a national holiday was the novelist Sarah Josepha Hale: a feminist Yankee abolitionist. Thanksgiving was against Southern values.

Christmas spread more or less nationwide in the 1840s and 1850s, although it did not become a legal federal holiday until 1870. But it was slowest to spread in New England and, although I don't want to overstate the case, there was at least some overlap between the people campaigning for Christmas in New England and the people campaigning for national unity and brotherhood, meaning appeasing Southerners on the slavery question. Thanksgiving spread out across the country as well, perhaps more slowly, because people kept moving west from New England to places like Michigan and Ohio and bringing Thanksgiving with them. So there was eventually an overlap where states celebrated both holidays, but Thanksgiving in November did not really spread in the South.

Thanksgiving, our holiday of national unity and togetherness, became a national holiday because the North won the war. Lincoln proclaimed Thanksgiving nine months after the Emancipation Proclamation. Sarah Josepha Hale was happy about both. American Thanksgiving was a victory for Northern abolitionist values.

We don't remember all of this story, because we don't like to remember it. Our country can never forget the Civil War, but we work very hard to forget the twenty or thirty years that led up to it. We like to talk about unity and civility and getting past partisan divisions. We don't like to remember that unity, civility, and compromise were key arguments for continuing to permit slavery. We forget that the opponents of slavery were called divisive and accused of tearing the country apart. If we remember that, we would have to remember that the Civil Rights Movement was accused of tearing the country apart, that Martin Luther King, Jr. was called a radical communist. We would have to remember that the people calling for unity and mutual understanding in the 1950s and early 1960s were calling for more sympathy for Southern segregationists and their feelings about their local traditions, that demands for justice were called unnecessarily confrontational.

We like to tell ourselves a story about a united, harmonious nation, joined in consensus. That story is neither true nor healthy. Our history is one of repeated confrontations over core national principles, and maybe most importantly a history of confrontation over race. And, time and again, Americans who stand up for racial equality, for America's best republican-with-a-small-r traditions, are accused of incivility and divisiveness. Because the cardinal rule of American political etiquette, in 1856 and in 1956 and in 2016, is that it is divisive and uncivil to take non-whites' side against one's fellow white people. How can you be so unpleasant and make such trouble, when surely whatever this problem is can wait?

That's still the story today, when there are public calls to unify behind the most divisive political figure in modern history, a politician who only sees some Americans as real Americans. The call for "unity" is a call to accept that racist, tribal definition of America, to "unify" by excluding a third of our fellow citizens and to pretend that they are not "really" American. That isn't unity. And that isn't the America I celebrate.

But Thanksgiving is a reminder of one old, deep strand in the American spirit, a strand that has stood by unpopular principle and resisted wrongful power. That's the spirit of the Pilgrim Separatists at Plymouth, and the spirit of the New England abolitionists who followed after them, with a heavy helping of Revolutionary patriots in between. I am grateful for that American legacy, which we need today as much as we ever have.