On Monday morning, New York Times columnist Paul Krugman asked why Donald Trump made this decision:

What Krugman left out, however, is the most likely explanation: (d) Trump is president of the United States. Nothing in this world is certain except death, taxes, and America betraying the Kurds.

The U.S. has now betrayed the Kurds a minimum of eight times over the past 100 years. The reasons for this are straightforward.