In a time of nihilism, power determines political purpose-the power of a passion or of a pressure group. The American political community is suffering from nihilism. It is manifest in the erosion of our moral tradition and in the reduction of our political system to a weakly umpired struggle of interest groups for control of public policy. More frequently than not, policy represents simply the lowest common denominator of group demands, a compromise among the passions. The incipient erosion of civil liberties in the face of the long-term decay of the tradition signals the approach of the master passion.