It is a truism that America has become a more diverse country. It is also a beautiful thing to watch. Visitors from other countries, particularly those having trouble incorporating different ethnic groups and faiths, are amazed that we manage to pull it off. Not perfectly, of course, but certainly better than any European or Asian nation today. It’s an extraordinary success story.

But how should this diversity shape our politics? The standard liberal answer for nearly a generation now has been that we should become aware of and “celebrate” our differences. Which is a splendid principle of moral pedagogy — but disastrous as a foundation for democratic politics in our ideological age. In recent years American liberalism has slipped into a kind of moral panic about racial, gender and sexual identity that has distorted liberalism’s message and prevented it from becoming a unifying force capable of governing.

One of the many lessons of the recent presidential election campaign and its repugnant outcome is that the age of identity liberalism must be brought to an end. Hillary Clinton was at her best and most uplifting when she spoke about American interests in world affairs and how they relate to our understanding of democracy. But when it came to life at home, she tended on the campaign trail to lose that large vision and slip into the rhetoric of diversity, calling out explicitly to African-American, Latino, L.G.B.T. and women voters at every stop. This was a strategic mistake. If you are going to mention groups in America, you had better mention all of them. If you don’t, those left out will notice and feel excluded. Which, as the data show, was exactly what happened with the white working class and those with strong religious convictions. Fully two-thirds of white voters without college degrees voted for Donald Trump, as did over 80 percent of white evangelicals.