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.

Politics and power is a realm of relative influence.

The markets are much more interested in America's long-term trajectory than they are in feeling that there is an acute short-term crisis.

I grew up in this world where everything seemed possible.

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.

I don't want to paint a picture of total gloom and doom.

What we see today is an American economy that has boomed because of policies and developments of the 1950s and '60s: the interstate-highway system, massive funding for science and technology, a public-education system that was the envy of the world and generous immigration policies.