If Dems can't pivot post-impeachment, their worst fear could become a reality
Julian Zelizer, a CNN political analyst, is a professor of history and public affairs at Princeton University and author of the forthcoming book, "Burning Down the House: Newt Gingrich, the Fall of a Speaker, and the Rise of the New Republican Party." Follow him on Twitter: @julianzelizer. The views expressed in this commentary are his own. View more opinion at CNN.
(CNN)The Iowa caucuses are almost here. Voters will have a chance to express their preferences among the Democratic presidential candidates on Monday after months of campaigning, advertisements and televised town halls and debates. While Iowa alone will not determine the party's nominee, it will mark the official start of the campaign season.