The third wave of democratization ended in the mid-1990s. In the following 15 years, there was relatively little new democratization and some regression toward authoritarianism. What can we learn from this period about the bases of both democratic and authoritarian regimes? The evidence suggests that democratic transitions and stability are not caused by international emulation effects or other highly contingent factors. Instead, national political cultures and socioeconomic structures are the two factors best positioned to explain the complex pattern of regime outcomes that now characterizes our world. Unfortunately, third-wave democracies are disproportionately afflicted by four sources of challenges to democratic consolidation: political polarization, over-powerful state structures in some cases, weak state structures in others, and to a lesser extent, the pro-authoritarian foreign policies of China and Russia.