Why did NATO intervene in Libya, but is not getting involved in Syria?
I know what you’re thinking: Oil!
Yes indeed, oil security was one of the key reasons for the NATO intervention in Libya, but even the rest of the international community lauded that mission, but has not been quite so enthusiastic in the case of Syria.
This is despite the fact that the Syrian crisis is seeing a growing number of casualties. These are now coming to a head of that of the Libyan crisis, and are likely to surpass it soon. 
Well, the Syrian crisis is a lot more complex than the Libyan crisis when looked in the context of international politics. Look at the maps of these two countries and note who their neighbors are.
Countries that surround Libya
Tunisia, Algeria, Niger, Chad, Egypt
Countries that surround Syria
Turkey, Iraq, Jordan, Israel, Lebanon
In the case of Syria, Turkey and Israel both are very strong military powers with interests in the area. Lebanon and Iraq are also heavily militarized with Jordan being a close military and political ally of Saudi Arabia, a state that has expressed concerns about Syria quite a bit lately. Here’s a quick analysis of the roles that Israel, Turkey and Iran (another superpower with an interest in the area) might play in this conflict.
Iran is well aware that the next major inter-state conflict in the middle east will more than certainly involve it in one way or another. Unfortunately for it though, its most important military allies are geographically far from it. Syria is an exception. Syria has a strong army by international standards and both Ayatollah Khamenei and Mahmoud Ahmadinejad are aware of this. Keeping Bashar Al-Assad in power and a close friend is of importance to them, and I believe that they are likely to get involved in any conflict over-throwing him (financially if not militarily). That must also mean that they are confident enough right now that the FSA will not succeed in over-throwing him.
Iran would like to see a stable Syria with Bashar Al-Assad in power.
Israel of course has the Golan Heights issue at play, which is a territory of Syria that is occupies. Though Golan Heights is the least important of territories occupied by it, by no means does it want to see a conflict there. As the Syrian crisis goes on, Golan Heights is likely to see an increasing number of displaced persons from Syria. The Israeli government would be obliged to offer refuge to this group which it likely will. Of their concern however will be the fear that a growing number of Syrian nationals in the region could cause revolts and general instability in the Golan Heights. For this reason, a stable Syrian government is of interest to Israel.
This is plain to see in rhetoric of the Israeli government. Recently, their deputy minister, Shaul Mofaz accused Syria of committing Genocide and called for international intervention. A government official also commented a few weeks ago that since Israel’s interests are being threatened and the international community is not doing anything about the situation, this is proof that Israel should take action in its own hands and not rely on others, speaking generally.
Turkey also has similar interests in Syria. Syria has a substantial Kurdish population at 9% . Syrian Kurds live largely in northern Syria, closer to the Turkish border and are likely to take refuge in that country were they to be expelled. We know that in war situations minorities are always the first group to be persecuted, and the Kurds are likely to be targets if the Syrian war spills a bit north. Turkey is well aware of this fact and does not want to see an influx of Syrian Kurds. It is afraid that with a confluence of its own population of the Kurdish people, the Kurds of Armenia, Iraq and Azerbaijan, and the new additions from Syria, it could lose the already tenuous control it has on them. Such an event would only strengthen the separatist Kurdistani movement and this would be against Turkey’s interests.
Turkey would also be pro-intervention hence and I believe that they are slowly walking down this path now. With the Turkish jet that was recently shot by the Syrian Army, Turkey has been propelled in a position where it has to take a staunch stand on the issue publicly. I think they are having a little trouble doing this because they are unsure of who their allies might be in such a conflict.
Given this assessment, for those of us who want to see an intervention in Syria for humanitarian reasons, we have to succeed in proving to the international community that Al-Assad is overthrowable. If we can provide any support (financial or even moral) support to the Free Syrian Army, I think we could convince Turkey and Israel (and subsequently the United States) to intervene. Iran might try and prevent such a coalition but would likely not act militarily against a strong pact. I think Turkey will have to take the first step and convince Israel manually. If these two countries get involved, NATO could be pulled in, either through Israel’s influence or Turkey’s NATO membership.