On Friday during a very small protest in the capitol city, security services shot and killed three demonstrators.

That action brought a few thousand Damascus residents into the streets just a stone's throw from the presidential palace and other government buildings - including the embassy of Iran that protestors singled out for its support of the regime.

New York Times:

Hundreds and hundreds of antigovernment protesters braved scattered gunfire from Syrian soldiers to march through a middle-class neighborhood in Damascus on Saturday, the biggest demonstration witnessed close to the heart of the capital since the country's uprising started 11 months ago.

The neighborhood, Mezze, skirts the hill on which the sprawling white presidential palace sits, and as row upon row of demonstrators walked along, wrapped tightly in heavy coats amid a snowstorm, more than a few expressed the wish that President Bashar al-Assad could hear them.

[...]

The relative calm of Damascus, as well as Aleppo, Syria's largest city, throughout the uprising has been cited repeatedly by the Assad government to buttress its argument that it enjoys wide support in Syria. Officials maintain that the demonstrations and unrest in rebellious cities like Homs, Hama and Dara'a, all sites of brutal government crackdowns, are the work of foreign infiltrators.

That argument will be much harder to sustain if mainstream, middle-class districts of the capital like Mezze begin rising up to demonstrate, as it did on Saturday. The march was prompted by the deaths of three men at a smaller protest a day earlier. Several marchers said it was one thing to deploy tanks in provincial cities to fight antigovernment protesters, but it would be impossible to say that foreign armed gangs had penetrated an area close to the presidential palace.

It is surprising that a crowd that large was able to assemble given the efforts of security forces to prevent such protests in the past. You can be sure that tomorrow, they will be more prepared.

All of this is heartening, except it won't do much good until we see cracks in Assad's main base of support; the army and his Alawite co-religionists. If he loses either group, his downfall will follow. But at present, there is no sign that the loyalty of his best troops or his closest political allies has wavered.