But as the arms-control scholar Thomas Schelling once noted, two things are very expensive in international life: promises when they succeed and threats when they fail.
The Berlin Wall wasn't the only barrier to fall after the collapse of the Soviet Union and the end of the Cold War. Traditional barriers to the flow of money, trade, people and ideas also fell.
America's growth historically has been fueled mostly by investment, education, productivity, innovation and immigration. The one thing that doesn't seem to have anything to do with America's growth rate is a brutal work schedule.