According to Matt Bai, the chief political correspondent for the New York Times Magazine, the progressive netroots upsurge of the mid-2000s and the rise of the Tea Party from 2009 to present are two variations on a common theme: they are "flash movements" born of online connections, cathartic urges and the devaluation of expertise. And unlike the big social movements of the past, he said both movements were merely oppositional and "ephemeral," unlikely to bring big changes to government. Speaking at a lunchtime forum here at the Shorenstein Center on the Press, Politics and Policy at the Harvard Kennedy School (where I am ensconced for the spring), Bai drew on his experiences writing about the netroots for his book, The Argument,...