Incidents
Presidents can sometimes use a fairly insignificant incident to start a war, and sometimes not. Wilson used the Lusitania to get us into WW1, a war that had no connection to American interests. Later LBJ used the Tonkin Gulf "attack" (which turned out to be mostly fake) to get us solidly into Vietnam, a guaranteed loss. Clinton
didn't use several major incidents (first Twin Towers bombing, Nairobi embassy attack, USS Cole) to start a war. Bush The Son used the second Twin Towers bombing to start a guaranteed-loss war against various randomly selected countries.
Obama has gone back to the Eisenhower/Clinton non-response mode, and most Americans are with him. We're in one of those momentary and transitory moods when we actually learn from history.
Now the Repoofs are trying to bring back the Wilson/LBJ/Bush mode, saying that the Libyan embassy attack justifies another war. It's not working. Their secondary attempt to use the same incident to discredit Obama isn't working either.
I don't know how long the current learn-from-history mood will last. The Repoofs seem to be betting it won't last long, betting that a constant hammering will eventually bring back war fever.