Of course there’s a difference between bad and worse
But there’s no reason to assume that your actions will send things from bad to worse. You could formulate the argument about Iraq thusly: Saddam threatened for years to get a nuke, showed no real sign of slowing down in that pursuit, and we took him out as a warning to other tinpot dictators in the region to knock it off. Remember the immediate aftermath of the invasion? Gaddafi surrendered his WMD program; Lebanon seemed like it was headed towards reconciliation; the Orange revolution blossomed. As things deteriorated in Iraq–in no small part due to the actions of men like Abu Ghadiya, terrorists who were operating out of Syria–those gains crumbled. We had a shot and we blew it by not having enough troops or the right strategy in place in Iraq.
Leaving that aside: Do you honestly think there’s any operational difference between having Hamas elected in Palestinian territories and having a strong man in power? If anything I think it’s a boon, since it gives us a clearer insight into the minds of the average Palestinian; no longer can the left claim that the average Palestinian simply wants peace. Both governments are equally corrupt and equally unable to enact peace with Israel. Furthermore, do you honestly think that Iran would have given up their nuclear ambitions without the invasion of Iraq, or that Bush’s increasing international scrutiny on their nuclear operation has allowed them to speed up the process?
Also: When does it become acceptable to enter a sovereign nation to take out a terrorist cell? You write that it’s okay to go into Afghanistan after the Taliban had attacked the embassies, the USS Cole, and the WTC. But why wait until the WTC? Would it have been acceptable to enter a sovereign nation after the attack on the Cole and the embassies? Just the embassies? Why after 9/11 but not before? In a sense, 9/11 really was the chickens coming home to roost but not for the reason the far left thought: this is what happens when you let a sore fester. It gets worse and worse until you suffer a real trauma. Ignoring a problem doesn’t make it go away.
Again: I would have preferred that the United States military use a lighter footprint with greater plausible deniability during their incursion into Syria. But we were well within our rights to do so and we shouldn’t refuse to cower away from our responsibility to protect our people. We let things slide too many times once. We shouldn’t do so again.