In a departure from the tradition of numerical taxonomy prevailing in the comparative study of political parties, Alan Arian and Samuel Barnes in 1974 provided a fascinating comparison of Israel and Italy-two party systems.' Using a combination of historical materials, survey evidence, and common political sense, they showed that despite their lack of absolute majorities in the electorate, dominant parties in such systems possess unusual political resources, permitting long-term governmental control and a neartotal exclusion of the opposition.2 Arian and Barnes's effort was unique in the annals of comparative politics, for they boldly compared what was generally considered a center-left dominant party, Mapai, with a center-right one, the Democrazia Cristiana, arguing persuasively that-even in the face of their differences-the two parties had developed similar mechanisms of control. Based on its domination of the pre-Independence Yishuv and its identification with the founding of the new state and with the dominant ideological tradition in Zionism, Mapai maintained itself in power long after its ideological elan had been weakened;3 although not solely responsible for founding the postwar Italian republic, the Christian Democracy (DC) held a similarly hegemonic role in Italy in no small part through its connections with the Catholic church, even though the level of consensus accorded it by the mass public was far weaker than that enjoyed by Mapai.4 Despite their differences-and those of their respective political systems-these dominant parties had enough in common for Arian and Barnes to compare them convincingly. Each represented a broad spectrum of the population. Although ideological in origin, both had become pragmatic in the instrumental use of power. Both were internally factionalized and had developed ties with a broad assortment of interest groups.5 Finally, each succeeded for a time in delegitimating an initially threatening contender for power: the left-wing communists in Italy and the right-wing nationalist Herut-then Gahal and today's Likud-in Israel.6