… is from page 350 of George Will’s excellent 2019 book, The Conservative Sensibility :
Founding this republic on interests rather than virtues was prudent because interests, unlike virtues, are always with us. They are spontaneous; everyone has them. To imagine not having them is to imagine being something otherworldly. Virtues are difficult to acquire, which is why virtuousness is much rarer than interestedness. This is why prudent people seeking to fashion a firm founding for a polity under popular sovereignty will not count primarily on virtue.