The missing piece here remains "why"? What vital US interest is at stake? What goals would we being trying to achieve by taking sides in this conflict? If winning is achieving your objective, how do we win if the objective isn't clear from the start?
Although it won't be articulated all that simply, the objective is a stable Syria and a stable region. It might not mean that the current opposition "wins" this, because it cannot be a simple zero sum game. Iran won't stand for it, and unless we are ready to throw down with Iran right now, the best approach is going to be a negotiated settlement which addresses Alawite and Iranian concerns. Bashir doesn't need to stay, but putting all the Alawites and the Sunni Syrians who have supported Assad out on their assses will definitely make a deeper mess.

This isn't a proposition of winning and I think anyone who is thinking like that in the beltway is delusional.