"The solution is covert support for the Sunni opposition funneled through Lebanon & possibly Turkey & Jordan

"... Therefore the likely solution is covert support for the Sunni opposition funneled through Lebanon and possibly Turkey and Jordan. It will be interesting to see if the Turks participate. Far more interesting will be seeing whether this works. Syrian intelligence has penetrated its Sunni opposition effectively for decades. Mounting a secret campaign against the regime would be difficult, and its success by no means assured. Still, that is the next move.
But it is not the last move. To put Iran back into its box, something must be done about the Iraqi political situation. Given the U.S. withdrawal, Washington has little influence there. All of the relationships the United States built were predicated on American power protecting the relationships. With the Americans gone, the foundation of those relationships dissolves. And even with Syria, the balance of power is shifting.
The United States has three choices. Accept the evolution and try to live with what emerges. Attempt to make a deal with Iran — a very painful and costly one. Or go to war. The first assumes Washington can live with what emerges. The second depends on whether Iran is interested in dealing with the United States. The third depends on having enough power to wage a war and to absorb Iran’s retaliatory strikes, particularly in the Strait of Hormuz. All are dubious, so toppling al Assad is critical. It changes the game and the momentum. But even that is enormously difficult and laden with risks...."