The expulsion of diplomats always looks like a weedy response to an atrocity, particularly one as outrageous as the murder of children at Houla. Unsurprisingly, news reports about kicking out the diplomats yesterday often concluded mournfully that the move wouldn't do much good.
This is true, but the presence or absence of diplomats is always symbolic. It increases the isolation of Syria, which will not in itself lead to the overthrow of the regime but will weaken it. Probably its most significant impact will be to sow doubts in the minds of Russian, Chinese and Iranian leaders about how much more political capital they want to spend to protect President Bashar al-Assad.
Before Houla, Syria was making some progress in persuading other powers that it was going to survive at least for the moment. The accusation that the ceasefire agreement reached by Kofi Annan was a smokescreen for doing nothing very effective in Syria was largely true. The Syrian authorities blithely ignored provisions about releasing detainees and allowing peaceful protests, but a military ceasefire left President Assad in control of much of the country.
It was in his interest to avoid any atrocity that would draw international attention. It is a measure of the lack of effective decision-making within the regime that they could not restrain their own forces. "Within the regime, there are divisions between the civilians, military and security," believes one commentator in Damascus. "There is not a single authority ruling the state but clusters of authority within the leadership."
Expulsion of diplomats ratchets up Syria's pariah status. It may persuade Syrians and the rest of the region that President Assad is not going to last beyond the short term. The lack of diplomatic representation will not doom the leadership. But certain changes will take place. De-legitimisation at home and abroad will be greater; it be will easier for Saudi Arabia and others to arm the opposition.
Russia, meanwhile, is visibly uncomfortable at being portrayed as the crucial support of child killers. Opponents of President Assad hope that the Houla massacre will be the turning point, but this is not wholly certain.