1. The British parliament, to the surprise (and probably relief) of Prime Minister David Cameron, rejected British armed intervention in Syria. Then Barack Obama, President of America, decided that he would ask for Congress approval even for what he called limited military action against the Syrian Government despite his right to declare war without the approval of Congress. In other words he is not really willing. It is a smart move on his part because if the venture fails Congress cannot blame him alone.
2. It looks like the Western Powers have learnt something from their experience in Afghanistan and Iraq. They once thought that it would take only a few months of shock and awe to achieve regime change in these two countries. In the event after ten years of war, after losing thousands of their own soldiers while killing hundreds of thousands of Afghans and Iraqis, devastating these countries, the regime changes have not resulted in the democracy they expected. If at all the present situation in these two countries is much worse than before invasion and the regime changes.
3. The hesitation over a military adventure in Syria, even a limited one is understandable. Yes, the use of chemical weapons probably killed over a thousand innocent Syrians. But already about 200,000 people have been killed. Is it acceptable to kill unlimited numbers of innocent people with bombs, rockets and bullets but not with chemical weapons?
4. If a military invasion is to take place surely it would cause more deaths, definitely more than the number killed by chemical weapons. And supposing the arsenal of chemical weapons are hit, would it not cause even more deaths.
5. Supposing limited war takes the form of assassination of the President, would the war stop? Would the opposition take over the Government and set up a democracy? The killings of Saddam and Ghadafi have not resulted in stability for their countries. Even the removal of Hosni Mubarak has not resulted in Egypt being stable and democratic.