“Are Americans as a people up to a major confrontation with another great power, whether in immediate conflict or a protracted Cold War-like struggle? It would be dangerous for a potential adversary to assume they are not. Whatever condition the American political system may be in, it is not appreciably worse than it was during the 1930s. That, too, was a deeply polarized America, including on the question of whether to intervene in the world’s conflicts. But once the U.S. found itself at war, dissent all but disappeared. If ever there could be a cure for American political polarization, a conflict with China would be it.”