This book studies the role of teachers’ unions in education reform, a substantively important topic that has received scant attention in political science. Teachers’ unions are the strongest and most active unions, and their leaders (a majority of whom are women) have shaped laws and have been elected to office. Mobilizing Teachers is a central contribution to the literatures of labor politics, social movements, and left-leaning parties because it is the first systematically comparative and historical analysis of the mobilizational strategies of teachers’ unions.

Chambers-Ju develops an argument that strikes a perfect balance between general theory and nuanced case studies of Mexico, Colombia, and Argentina. He argues that the internal organization of unions shapes their choice of strategies. Unions can be hierarchical (or not) and can have one (or more) factions. If unions exhibit internal hierarchical relations (i.e., a clear chain of command that links local and national leadership), they can deliver votes to parties and, therefore, can choose to join electoral politics. These internally hierarchical unions can exhibit one or more factions.

If there is a hegemonic single faction, union leaders form a unified voting bloc that will join alliances with the party that seems most likely to win the elections and that makes the