Today's visit to Damascus by Turkey's foreign minister is a watershed in Syria's modern history.
The visit marks the beginning of foreign intervention in the country to install a new regime and alter the balance of power in the region. Iran will lose its Syrian protege and Russia will keep its naval base in Tartous.
Turkey is a member of NATO but also capable of playing its own game; it can easily intervene militarily (with NATO's blessing) to help remove Assad while appeasing Russia. Its own prize will be stronger political and economic influence in the region and as a bonus more Kurds will choose to live in Syria rather than Turkey! Israel will cautiously play along if the new regime will be more interested in re-building Syria than recovering the Golan for the next decade or so.
If Assad and his brother are not assasinated in the next few months or El-Qardaha is not flattened by fighter bombers, Turkey will surely want to establish an exclusion zone deep into northern Syria as a first step towards whipping the Assad clan into submission. The regime has some strong ground troops (essentially two loyal and well-equipped Alawite divisions) but no real air cover and the country can also be "invaded" from the sea and from the east.
There is always a heavy price to pay for foreign intervention and no wise and patriotic Syrian wants it. Sadly it is now almost inevitable. Peaceful protesters and the smattering of anti-regime armed groups are simply incapable of putting an end to the regime's daily murders. Conservative Arab regimes and foreign powers, with their own political agendas, have seen Assad shoot himself in the foot and will now move in for the kill. Perhaps they will be motivated to do it before the economy becomes too much of a liability!
Why can't Assad do the honourable thing, save the nation and his own skin and just quit?