There were arguments that intervention in Libya was not in the U.S. national security interest

[pinboy3niner]

18. I'm one of those who supported the Libya intervention and oppose this one

There are similarities, but in Libya the proximate event was not CW use, but imminent threat to a civilian population in Benghazi. Libyan tanks had already made one incursion into the city, and were poised to fire indiscriminately against the population.

In that case, the UN acted under its Responsibility to Protect (R2P) initiative. http://en.wikipedia.org/wiki/Responsibility_to_protect

Syria is more a case of enforcement of "international norms" than R2P. Military action is only one of the responses contemplated by the UN as appropriate.

And while "standing up" for these principles is important, military action is not always the best response. Especially when it's doubtful that a military response will achieve its objective(s) and when the repurcussions of a military response may lead to a graver humanitarian crisis.

Sometimes the "cure" CAN be worse than the disease, and discretion is the better part of valor.