Some researchers find a substantial increase in political tolerance since the 1950s, while others find the increase to be “illusory”—the public is more tolerant now of leftists, but has simply found other targets on which to vent its intolerance. Reanalysis and the addition of more extensive trend data from 1940 to 1985 suggest that the shift does seem primarily to reflect increased tolerance of leftists, but that the public has not found other groups to be intolerant of. Measured tolerance has fluctuated greatly over the period, reflecting mainly changes in perceptions of threat from putatively subversive groups, especially domestic Communists. Also, the public's grasp of, and selfinterested concern about, civil liberties seems so minimal that one might argue not that the public is substantially tolerant or intolerant, but that it has no really tangibly measurable “attitude” on the subject one way or the other.