U.S. President Barack Obama addresses troops at Bagram Air Base in Kabul

Suddenly, it seems, the world is at war.

In Iraq, armed and angry militants of the Islamic State of Iraq and Syria (ISIS) are at the gates of Baghdad. In Pakistan, government forces are mounting a ferocious campaign against the Taliban in North Waziristan. In Syria, the civil war drags on. These are “hot wars” involving the clashing of troops and weapons. Having escaped such “hot” conflicts in Iraq and Afghanistan, these are the sort of war Americans have made it plain they are not prepared to fight.