Foundational scholarship on constitutional regime type favors parliamentarism over presidentialism on grounds that the former fosters democratic stability by better aligning the interests of legislatures and executives. Yet, presidentialism and constitutional hybrids that combine a popularly elected president with a cabinet subject to parliamentary confidence remain abundant even among regimes that engaged in constitutional engineering in recent decades. This chapter describes the key features that distinguish these regime types and how they vary empirically among democracies. We focus especially on how presidents are elected and on the policymaking powers they wield, such as decree authority, control of the legislative agenda, and the veto. We review two trends from recent decades—loosening restrictions on presidential reelection and legislative replacement of presidents during government crises—that suggest convergence with parliamentarism in practice.