Framed within broader debates about how and why changes in foundational definitions of the nation occur, Shelef's analysis centers on the mechanisms of ideological change and then subjects them to empirical scrutiny. He thus moves beyond the common but problematic assumptions that such transformations must be either a rare, rational adaptation to traumatic shock or a relatively constant product of manipulation by power-hungry elites. He finds that nationalist movements, including radical and religious fundamentalist ones, can and do change cardinal components of their ideological beliefs in both moderating and radicalizing directions. These changes have more to do with the unguided consequences of engagement in day-to-day politics than with strategic reaction to new realities, the use of force, or the changing incentives of leaders. Engaging with some of the most contentious debates about the nature of Israeli nationalism and the geographic, religious, and ethnic definition of the state of Israel, Shelef has made signal contributions to our understanding of Middle East politics and of the ideological underpinnings of nationalism itself.