Chapter published in The Oxford Handbook of the American Presidency.

Since the 1930s, the Gallup organization has asked Americans “do you approve or disapprove of the way [the incumbent] is handling his job as president? ” This is a fundamental question for democratic politics, tapping the public’s evaluation of the nation’s most powerful government official. Public support for the president shapes the give and take of politics in Washington, D.C. High approval ratings can be a powerful resource for presidents as they work to achieve their policy goals while low or eroding ratings can make it harder to move the president’s agenda (see Edwards 2009 for an extended discussion). Reflective of its normative and political significance, survey measures of presidential approval have become ubiquitous; one website regularly updates an estimate of presidential approval based on results from 17 polling organizations.1 At the time of this essay, the Gallup organization alone has asked the approval question 262 times during George W. Bush’s presidency.2 Presidential approval is widely reported in news media, routinely discussed among the chattering classes, and has been analyzed at length by social scientists since John Mueller’s (1970) seminal study. Almost four decades of research has taught us much about public evaluations of the president, but the march of history—new political and historical conditions