Political regime changes and conflicts over such transitions often occur in clusters and advance like waves. As one country transforms its constitutional framework, discontented actors in other countries take inspiration from this precedent and start to undertake similar efforts. The frontrunner’s success encourages them to challenge their own rulers and push for transforming the way in which political authority is exercised. As a result of such demonstration effects, regime contention frequently snowballs and sometimes triggers avalanches (Markoff 1996; Berg-Schlosser 2009; Hale 2013). For instance, the French revolutions of 1830 and especially 1848 set in motion dramatic diffusion processes; within one month of “Citizen King” Louis Philippe’s overthrow in February 1848, half of Europe stood aflame, engulfed by protests and rebellions against autocratic princes (Sperber 1994; Dowe et al. 2001). The Russian revolutions of 1917 also spurred contention and regime change throughout Central and Eastern Europe from 1917 to 1919, and the “third wave of democratization” that started in Southern Europe in 1974 rippled across the world during the subsequent two decades (Huntington 1991; Kurzman 1998; Markoff 2009; Lehoucq 2011; Mainwaring and Pérez-Liñán forthcoming).

These waves of regime contention have had divergent characteristics, however. The differences in timing are particularly striking. Regime conflict during the third wave unfolded over the course of two decades (1974 to early 1990s), whereas the 1848 revolution spread explosively within days (Traugott 2010: 131–42): Louis Philippe’s downfall on February 24 triggered mobilization and protests in Baden on February 27 (Real 1983: 47–50), Stuttgart on March 3, Munich on March 6–7, Vienna on March 13–15, Berlin on March 18–19, and Copenhagen on March 20–21. Beginning in April, it also had repercussions in faraway Brazil (Quintas 2004: 67–95), Colombia (Posada-Carbó 2002: 224–40), Chile (Collier 2003: 79, 84–92; Wood 2011: 158–64, 193–202), and even the United States, where it helped set the context for the July 1848 Seneca Falls Convention for women’s rights (Howe 2007: 846–47; broad overviews in Dowe et al. 2001 and Thomson 2002; see also Hobsbawm 1996a: 10–11).