When you decide to get involved in a military operation in a place like Syria, you've got to be prepared, as we learned from Iraq and Afghanistan, to become the government, and I'm not sure any country, either the United States or I don't hear of anyone else, who's willing to take on that responsibility.
What we will not wait for is that particular nexus of terrorism, weapons of mass destruction that is extremism, and the technology to come together in a way that is harmful to the United States.