Syria, as with Afghanistan, Iraq, Iran, Saudia Arabia, etc., is one more Arabic country where the people agree on nothing. They can't agree on religion, politics, leadership or culture. They fight with each other when they agree, disagree, or have no philosophy at all. They fight with each other and kill each other. And they fight and kill anyone who offers assistance. They are with America one day and against it the next. The people support us when we are there and oppose us as soon as we leave. They help the terrorists when they are present and support us when we are present. We share neither their culture nor their religion. They generally despise American culture, politics, philosophy and economics. And there we are, trying to save their people and change their world. There we are, confronting their political leadership, fickle allegiance and religious fanatacism. This has been going on in Arabic societies for thousands of years and the people, no matter how oppressed, either yield to it or migrate. And how have we ever changed it? But there we are with our soldiers. Fifteen + years in Afghanistan, a country even Russia found hopeless. The populace apparently aren't willing to unify and oppose their enemies. But they will let us try to do it when it is to their convenience.
We apparently learned nothing from Vietnam.