Apparently it's having a reformist temperament

To put it simply, Gopnik organizes the Right, Left, and liberals according to reaction, revolution, and reform. There’s a certain clarity and accuracy to the division, but because Gopnik’s idea of politics is primarily based on individual temperament, he’s drawn to a classification system that is essentially psychological. In his schema, conservatives are reactionaries, leftists are revolutionaries planning to bomb their way to utopia, and liberals are reformers committed to what Max Weber called the “slow boring of hard boards”—that is, parliamentary politics. This is how they’re oriented under liberalism, but liberals turn revolutionary when exposed to kings, and Marxists plan to proceed from proletarian dictatorship to communism step by nonviolent step. Hell, there’s even an important place in monarchism for wise royal reforms. But Gopnik is so committed to the temperamental model that he has been moved to question the wisdom of foundationally liberal campaigns up to and including the American Revolution.