Because it started as an offshoot of al Qaeda in Iraq, ISIL has long been subject to U.N. sanctions, and all countries have a legal obligation to freeze its assets and prohibit its business dealings. But countries around the world need to do more to make these sanctions work.

There's no connection between al-Qaeda and Iraq.

At the U.N., I routinely encounter countries that do not want to impose sanctions or even to enforce those already on the books. The hard-line sanctions skeptics have their own self-interested reasons for opposing sanctions, but they ground their opposition in claims that America uses sanctions to inflict punishment for punishment's sake.

In the 2000 election, George W. Bush, who had shirked military service, succeeded in presenting himself as more reliable on national security than Al Gore.

Countries that intervene militarily rarely do so out of pure altruism.

The reality is that al Qaeda has been trying to attack the United States since long before Iraq.