Charles Kenny delivers a reality check:
It’s not just that the link between growth and particular policies is weak—so is the link between growth and politicians as a whole, whatever their ideological persuasion. Bill Easterly and Steven Pennings of New York University looked for (PDF) evidence of the impact of national leaders on growth since 1960. Their findings suggest that, if national leaders matter anywhere, it’s in autocracies rather than in democracies like the U.S. and Europe. But even in autocratic regimes it’s hard to pinpoint the influence of individual leaders on economic growth—good or bad. Some leaders were in charge during periods of high growth and some during periods of low growth, but no more often than you would expect if random chance rather than leadership quality was driving the results. Across 50 years and 100 countries, they suggest, 2 percent of the variation in growth rates might be explained by political leaders—with 98 percent accounted for by other factors.