I think it's a mistake to rely too much on any one economic factor. It's why investors try to spread their portfolio round.

Poles understand perhaps better than anyone the consequences of making toothless warnings to brutal tyrants and terrorist regimes.

It's a very bad thing when people exterminate other people, and people persecute minorities.

The Bernie Sanders phenomenon shows that it's not confined to Republicans. There is a general sentiment that America is on the wrong track.

One of the things that ultimately led me to leave mathematics and go into political science was thinking I could prevent nuclear war.

The only way you can be comfortable about Donald Trump's foreign policy, is to think he doesn't really mean anything he says.

The truth is that for reasons that have a lot to do with the U.S. government bureaucracy, we settled on the one issue that everyone could agree on, which was weapons of mass destruction, as the core reason.