We have SEAL's & CIA operatives all across the globe, especially in the middle east. Under your parameters, we're currently invading pretty much every country in the middle east. We have military &/or CIA assets in pretty much every hot spot on the globe. Those aren't "invasions". Invasion, is used by folks like yourself to imply some massive 10,000 soldier crossing the border.
Now, if you want to re-re-re-re-re-re-re-re-re-re-debate the merits about going into Iraq, start a new thread. But that's not the reason the middle east is blowing up like it currently is. It's CURRENT policy of plactating, appeasing, and spending more time working with our enemies than our allies. A few drone hits, here, combined with sticking our head in the sand, until they supposedly run out of local victims isn't a plan.
So, 1 more time.....this is NOT about invading any other country, or trying to reform any other government. ISIS is a global threat, targeting anyone that doesn't comply with their radicalized version of Islam. And if you actually believe they don't have their sights set on terrorizing & targeting the U.S., you are being seriously near sighted