What does al Qaeda have in common with Amnesty International and Greenpeace? All three are loose networks of individuals united by a shared passion for a single cause, and thanks to cheaper communication and transportation, each can project its influence globally. Their funding comes from small contributions made by thousands of sympathizers and from large sums given by a few major donors, while their effectiveness derives from the single-minded devotion of their idealistic activists. The difference, of course, is that while al Qaeda’s suicidal terrorists want to bring down Western civilization, the members of Amnesty International, Greenpeace, and other such nongovernmental organizations (NGOs) want to make it better. And in many cases, they do.

By any reckoning, the 1990s were a good decade for NGOs. The rise of these nimble organizations has—with the exception of the al Qaedas of this world—been a generally positive development. But it also highlights a troubling decline in the fortunes of political parties. Indeed, the weakening of broad-based parties that aggregate disparate interests at the national level and that help stabilize the natural volatility of domestic politics is unfortunate. Moreover, at a time when countries are periodically destabilized by foreign shocks, from financial crashes to terrorism, the domestic volatility that usually coexists with a weak party system is even more troubling. Fittingly enough, the best way for political parties to recover their lost vigor may be by emulating some of the practices that have made NGOs such a success.
During the 1990s, from Germany to Peru, angry voters...