If [Bush's] successors don't screw it up, within 10 years NASA will have us back to where we belong -- on other worlds.

To understand the workings of American politics, you have to understand this fundamental law: Conservatives think liberals are stupid. Liberals think conservatives are evil.

There is a mystique about psychiatry that people think that you have some kind of a magical lens, you know, Superman's X-ray vision into the soul. One of the reasons I left psychiatry is that I didn't believe that.

Where there is a confluence of interests among nations, as, for example the swine flu or polio, you can get well functioning international institutions like the World Health Organization. And you can act. Climate change is different, because the science remains hypothetical and the potential costs staggering.

This week, Iranian-backed Houthi rebels seized control of the Yemeni government, heretofore pro-American. In September, they overran Sanaa, the capital. On Tuesday, they seized the presidential palace. On Thursday, they forced the president to resign.

This is a formidable enemy. To dismiss it as a bunch of 'cowards' perpetuating 'senseless acts of violence' is complacent nonsense. People willing to kill thousands of innocents while they kill themselves are not cowards. They are deadly vicious warriors and need to be treated as such.

There are cycles in American politics. US cycles are even more pronounced because we Americans have a totally entrepreneurial presidential system. We don't have parliamentary opposition parties with a shadow prime minister and shadow cabinets. Every four years, the opposition reinvents itself.