Read Garen Christopher Kaloustian's argument, “Why ‘Christian nationalists’ are liberals — whether they realize it or not,” here. What he cannot plausibly do is declare the entire American political inheritance illegitimate. What today's Christian nationalists generally mean by "nationalism" is not that every ethnic group in America should receive its own sovereign state. And Christian nationalists add that Christianity is part of the country's inheritance and ought to have some meaningful place in its public life. And if there is such a thing as an American conservative, he must presumably believe there is an America to conserve.