President Obama’s on-and-off-again planned American attack on Syria is nothing new. Besides its five declared wars, America has a habit of intervening all over the world.

Even apart from clandestine CIA operations, and even after the unhappy end of the Vietnam War, we have attacked lots of countries and non-state militias. The roll call of recent American military interventions is quite astounding: Cambodia, Iran, Libya, Lebanon, Grenada, Panama, Liberia, Iraq, Haiti, Somalia, the former Yugoslavia, Zaire, and Afghanistan.

Even the notion of past American isolationism is a myth: In the four years between 1912 and 1916 alone, the U.S. sent troops into Cuba, Panama, Honduras, Nicaragua, Mexico, the Dominican Republic, and Haiti. And those busy years of intervention were not novel: Since our nation’s infancy, the U.S. military has been constantly engaged. In another four-year period, between 1812 and 1816, America fought the British, the French, the Spanish, and the North Africans....