We could use vague language like harbors terrorists or funds terrorists. More realistically, though, I perceive ISIS as a greater threat to US national securit

We could use vague language like harbors terrorists or funds terrorists. More realistically, though, I perceive ISIS as a greater threat to US national security. As an example, the TSA is already getting more ornery with airport security in response to the Russian airplane downed over Egypt for which ISIS has taken responsibility. And ISIS only claims responsibility as revenge against Russian intervention in Syria, intervention on behalf of the government of Syria. If Syria is a threat, it's a lot less pressing than the threat posed by the militants fighting Syria.