The Islamic State attacks in Paris exposed two vulnerabilities. The first is ours, to the threat posed by skilled, suicidal fighters. Yet the massacre also exposed a weakness of Islamic State, one that threatens its very existence. The threat posed by suicide attackers is all too real, and as long as the conflict in Syria and Iraq continues, there will be a supply of trained fighters to challenge Western societies, especially Europe. Yet Islamic State has had the capacity to attempt this type of attack in Europe for years, but chose not to. Paris indicates that its leader, Abu Bakr al-Baghdadi, has now committed to a strategy of provocative, international terrorism. That's a doomed strategy: It imposes additional costs on an enterprise that is already spread too thin for its resources.