One of the great challenges of sustainable development is to combine society's desires for economic prosperity and social security. For decades economists and politicians have debated how to reconcile the undoubted power of markets with the reassuring protections of social insurance. America's supply-siders claim that the best way to achieve well-being for America's poor is by spurring rapid economic growth and that the higher taxes needed to fund high levels of social insurance would cripple prosperity. Austrian-born free-market economist Friedrich August von Hayek suggested that high taxation would be a "road to serfdom," a threat to freedom itself.*

Most of the debate in the U.S. is clouded by vested interests and by ideology. Yet there is by now a rich empirical rec-ord to judge these issues scientifically. The evidence may be found by comparing a group of relatively free-market economies that have low to moderate rates of taxation and social outlays with a group of social-welfare states that have high rates of taxation and social outlays.