Julian Zelizer is a professor of history and public affairs at Princeton University. He is the author of "Jimmy Carter" and of the new book "Governing America."

(CNN) -- The critics are raving about Steven Spielberg's new film "Lincoln." A.O. Scott of the New York Times called it "among the finest films ever made about American politics." Viewers get a taste of the legislative process up close by watching how President Abraham Lincoln rounded up the necessary votes in get the 13th Amendment resolution through the House. Viewers see a master at work -- a president who knew how to break through the various divisions in Congress and outflank his opponents.

Movies such as Spielberg's often result in inflated expectations about what a president could achieve in the current political environment. The reality is that even the best presidents would have trouble rounding up votes in the contemporary Congress.

As the nation continues to be obsessed with a sex scandal involving top military officials and as the lame-duck Congress figures out what to do about the fiscal cliff, Washington would do well to think seriously about how government reform might improve the basic machinery of the federal government so that elected officials are better able to handle the big issues of the day such as unemployment, immigration, climate change and more....