The Anatomy of the 1989 Wave

In a single year, communist regimes fell across Europe in a contagious cascade. The anatomy of the wave is instructive. Moscow under Gorbachev renounced the Brezhnev doctrine of military intervention, removing the ultimate guarantor of each satellite regime.

Hungary opened its border with Austria in the summer, letting East Germans escape west and hollowing the Berlin Wall from behind. Poland negotiated its exit through a roundtable, showing the region that communists could lose and live. Leipzig, Prague, Bucharest, and Sofia then each passed the local tipping point within weeks.

The wave demonstrates how legitimacy cascades: once one domino fell without Soviet tanks, every crowd knew the regime had lost its final argument..