When we say "isolate Syria" we mean isolate them from U.S. or, at best, North American and European trade. This would not affect them very much- what vacuum would be created would be gladly filled by the Russians and Chinese who, if you haven't caught it, are doing a great job supplying Syria and Iran with weapons technology and likely political advisors as well.
Specifically, speaking about the Chinese now. They have beaten us at our own game. While they are not Japan, they still own hundreds of billions of our debt that we (America) spent to continue to feed our very hungry, very strong defense industries. Basically they have been buying our debt. I won't go into the complications of having to essentially borrow (with interest) staggering sums of money from sworn ideological enemies but you can guess.
And they're still buying it up. Why use tanks and soldiers when you can sell off those Treasury Securities and deal us a more crippling blow than a single nuclear weapon. Also, you drop a nuke or invade and you galvanize the American populace against you. You sell off our Treasury Bonds and you use capitalism as a very deadly weapon against an economy.
PB