Kevin Williamson of National Review Online focuses on the fascination and fear of radicalism in American politics.

The fear of radicalism runs deep in our national DNA. So does the love of it. It’s democratic politics as the ultimate on-again/off-again romance.

The Founders themselves feared that various centrifugal tendencies — faction, passions, democracy itself — would turn the country away from its republican virtues and hence from its shared purpose and ideals, replacing these with various radical enthusiasms. Our progressive friends who at the moment are in a rage about the limits our Constitution puts on democratic passions are a very good example of why those limits were put in place.

Americans have frequently followed a pattern of flirting with radicalism of one kind or another — usually nationalism, and usually in a time of war — and then retreating from the edge when the crisis has passed. Woodrow Wilson’s “war socialism” pulled the United States in a distinctly national-socialist direction, and Warren G. Harding’s “return to normalcy” campaign pulled it back. After the trauma of the Great Depression and World War II, the grasping autocracy of Franklin Roosevelt’s government — his New Deal was a frankly nationalist enterprise, from its politics to its aesthetics — limped on during the Truman administration but was dissolved during the Eisenhower years, a time of broad and deep but not radical conservatism.