Barack Obama claimed resounding victory in two presidential elections on the strength of a genuinely conservative conception of pluralistic American identity that embraced and celebrated America as it exists. Yet this unifying vision, from the mouth of a black president, primed the ethnonationalist backlash that put Mr. Trump in the White House.

The molten core of right-wing nationalism is the furious denial of America's unalterably multiracial, multicultural national character. This denialism is the crux of the new nationalism's disloyal contempt for the United States of America. The struggle to make good on the founding promise of equal freedom is the dark but hopeful thread that runs through our national story and defines our national character. It's a noble, inspiring story, but the conservative nationalist rejects it, because it casts Robert E. Lee, and the modern defenders of his monuments, as the bad guys -- the obstacles we must overcome to make our nation more fully, more truly American.

Without obstacles, there is no story. The rise of Trumpist ethnonationalism opened a new chapter, a new variation on the primal American theme, and its outcome will again define us. We must remember that it's our story, that we write it -- with our bodies, our money, our voices, our votes. And we must never lose the thread.

To reject pluralism and liberalizing progress is to reject the United States of America as it is, to heap contempt upon American heroes who shed blood and tears fighting for the liberty and equality of their compatriots. The nationalist's nostalgic whitewashed fantasy vision of American national identity cannot be restored, because it never existed. What they seek to impose is fundamentally hostile to a nation forged in the defining American struggle for equal freedom, and we become who we are as we struggle against them.