This article develops a system for analyzing the aggressiveness of journalists' questions to public figures and applies that system to a sample of presidential news conferences from Eisenhower through Clinton. The primary objective is to use the phenomenon of aggressive questioning as a window into the White House press corps and its evolving relationship to the presidency. Ten features of question design are examined as indicators of four basic dimensions of aggressiveness: (1) initiative, (2) directness, (3) assertiveness, and (4) adversarialness. The results reveal significant trends for all dimensions, all indicating a long-term decline in deference to the president and the rise of a more vigorous and at times adversarial posture. While directness has increased gradually over time and is relatively insensitive to the immediate sociopolitical context, initiative, assertiveness, and adversarialness are more volatile and sensitive to local conditions. The volatile dimensions rose from the late 1960s through the early 1980s, declined from the mid-1980s through the early 1990s, and rose again at century's end. Possible factors contributing to these trends, and their broader ramifications for the evolving relationship between the news media and the presidency, are also discussed.