The U.S. president is often called the "leader of free world." But if you ask an economist or a Constitutional scholar how much the occupant of the Oval Office matters, they won't say much. We look at what the data have to say about measuring leadership, and its impact on the economy and the country.

What do Renaissance painting, civil-rights movements, and Olympic cycling have in common? In each case, huge breakthroughs came from taking tiny steps. In a world where everyone is looking for the next moonshot, we shouldn't ignore the power of incrementalism.