In Syria Arabs are killing Arabs. This is better than Arabs killing Americans or Arabs killing Israelis. What's wrong with the present outcome? Nothing.
A truly Machiavellian approach would be to covertly provide support to whatever side appears to be losing. A less evil and more morally supportable approach is what we are doing now. Nothing.
The longer the conflict goes on the more the Arab world gets wrapped up in civil war, one sect versus another. Our role: sympathetic spectators doing ... nothing.
Perhaps the Turks and the Persians and the Kurds will get involved too, even the Berbers. How sad.... When one's opponents in the Long War begin to fight each other, all we need do is watch approvingly and remember to do exactly ... nothing.