The Syria situation is very tragic and very messy. I want to put down some thoughts and see if people think I am on the right track. I think some of the arguments I see from both sides are missing the point.
Behind the scenes, the argument being made is about Iran.
I suspect that the administration thought that the Iran hawks would back action against the Syrian regime because Syria is Iran's most important ally in the region. If the Assad regime fell, it would be a severs strategic blow to Iran, and to Hezbollah. Maybe Obama thinks that if Assad falls, he will face less pressure to start a war with Iran later. As far as I am concerned, if that is the real reason, they should just come right out and say so. But politicians don't work that way.
If there is an action, it will not be a quagmire.
The model they have in mind is Libya. In pure military terms, the Libyan action was a great success. The bombing tipped the scales in favor of the rebels in Libya, who won the battle. The same thing could tip the scales to the rebels in Syria. Of course, the victory of the rebels in Libya did not usher in a democratic paradise, and it won't in Syria either. But if you do not put in ground troops, it is a lot easier to start and to stop an action. I do not see any possibility of American ground troops. Why would they need to, since the rebels are fighting hard, and air power intervention against the government would take away the government's biggest military advantage, its heavy weapons and air power. I think Obama's military doctrine is to use air power, including drones, to avoid having to commit ground troops.
It would be pointless to do anything unless we supported one side on the civil war.
If we are going to intervene in a war that is already going on, there is no point to do so unless we want to help one of the sides win the war. A purely punitive "message" attack does not make any sense. It will accomplish nothing. If the US wants to deter a nation from using chemical weapons in a war, the only way to deter anyone is to take a side in the war. Of course, it is doubtful if we should be taking sides in this war.
US military intervention in Syria would not help US strategic interests or humanitarian concerns.
The rebels in Syria appear to be dominated by extremists who don't like us. If they win, the country will be dominated by armed gangs, as is happening in Libya. After a long bitter war, atrocities from both sides become more likely, no matter who wins. I see no possibility that a new Syrian government would be interested in peace with Israel.
The United States needs to turn to its own affairs, and not try to control the rest of the world.
This country has to deal with the economic inequality, growing poverty, and financialization that is dragging us down. The rest of the world does not want us to be controlling it. I have heard stories about how foreign countries in private ask for an active US policy, but they won't support such a policy publicly. If the world wants the US to help with some dangerous or violent situation somewhere that does not directly impinge on our country's citizens, then they better come out with broad public and material support for any action the US takes before we consider such an action. Empire is a burden, and in my opinion is not worth it.