This book fills a gap in constitutional law by investigating the global trend towards substantive constitutional adjudication of electoral legislation. On which premises is this judicial scrutiny grounded, what can explain the trend and with which consequences for representative democracy? So far, scholars have focused their attention on a few countries and on selected judgments, such as the US Supreme Court's landmark decision in Citizens United v. FEC. This book offers instead a comparative reading of the issue by analysing how the circulation of models and arguments between judges has triggered the progressive overcoming of a traditionally deferent approach towards electoral norms, which still survives in a few jurisdictions. The book explores the democratic underpinning of electoral systems and their evolution. It explores the methodological choices constitutional judges are confronted with when managing electoral legislation. This prepares the ground for the in-depth review of the case law in thirteen legal systems, across North and South America, Africa, Asia and Europe, with a view to identifying the underlying concept of democracy courts seek to advance. The authors critically discuss the ideas of democracy that can be detected in each jurisdiction. This includes the use of constitutional borrowing, and the effects of the judgments on the relationship between courts, representative institutions and the voters. Given the global reach, the combination of theoretical and practical approaches, and the comparative assessment provided, this work is of interest for academics in the field of law, political science and philosophy, and for policy-makers and judges in constitutional democracies across the continents.