This essay discusses the rationale guiding legislation dealing exclusively with political parties. The analysis is based on examination of party laws in, Austria, Finland, Germany, Israel, Poland, Spain and Venezuela. The manner by which a particular legislature applies the general features of party law legislation (general declaration regarding the role of parties in democracies, definition of parties, registration requirements, the democratic character of association in parties, regulation of party finance, legal sanctions) is demonstrated in reference to the Israeli party law, the most recent case of an established democracy whose legislature passed a parties law in 1992. Throughout the analysis, the study addresses a question of principle: should a legislature comprised of representatives of political parties undertake to legislate laws regulating the activities of political parties in a democratic parliamentary system? It is suggested that a partial response to this question is found in the fact that, with the exception of Finland and Israel, democratic polities that have chosen to legislate party laws had previously experienced a collapse of their democratic systems. In the process of reforming their democratic structures, the legislatures in these polities enacted parties laws that would ensure that political parties perform functions commensurate with the goals and practices of modern democracies.