They wouldn't intervene because Syria is Iran's satellite, and they fear Iran's terrorist retaliation. They wouldn't intervene because they are already stretched thin from Libya to Pakistan. They wouldn't intervene because Syria has no oil, and because they are plain stupid to intervene in Libya, -whose dictator stopped being a menace and a source of terrorism outside Libya- and thus, by being in Libya, they have no stomach for yet another uncertain war in the volatile Arab world, both politically and militarily.
Monitor: Clashes near Damascus despite truce there, five killed in Aleppo (Reuters)
from the article: At least 88 protesters killed in deadliest day of Syria unrest