A world-wide islamic terrorist state based in Iraq/Syria is definitely a threat to the USA.
The US should not run away from the mistakes made by Bush and Obama. Today at least 30,000 of the most radical lunatics from all over the world have come to join ISIS. The US has a chance to wipe some of the world's most dedicated and willing islamic terrorist nutcases.
The strategy of shoveling flies is no more effective than the strategy of taking real estate when waging an asymmetrical war involving terrorism. You are right, a worldwide Islamic terrorist state is a threat to the USA but the idea that its "center" is Iraq/Syria leads to a confused strategy, a strategy which led us to invade Iraq in the first place. If we were to tame Iraq tomorrow, the jihadist threat would still be extant from China to well along the Mediterranean coast, Iraq is only a place. When we occupied Iraq did we come any closer to preventing 19 box cutter welding fanatics from attacking America the next time? Of course not. This war is not a war for geography, not a checker game in two dimensions in which spaces are taken and held, it is a three or four dimensional war which must be seen in those terms.
If in one of the highest honors in hell where Osama bin Laden is no doubt roasting for eternity he might if he is capable look upon our misadventure in Iraq as the fruit of his attack on 9/11 and he could not be better satisfied with the outcome. Similarly, for the United States to get mixed up in Iraq now by any means other than determined aerial bombing would be almost as damaging to our security.
I have posted from the very beginning of the Obama war in Iraq that the enemy is not really Isis, the real enemy was and remains Iran. Iran has the infrastructure and will soon have the bomb. At that point the geographical balance of power in the region will be stood on its head and America will be even more obviously on the run. This is more than a checker board move, the bomb will change everything.
We must start to think in these terms and get rid of the idea that we can win in Vietnam this time.
Every Muslim is a potential terrorist. Are we going to wipe them out? Hardly. The only way these crazy a-holes can hurt us is if we let them into our country, which we are doing now. Our corrupt politicians are bringing the enemy here by the thousands. Nothing we do overseas will matter. We are welcoming our own destruction into our nation. That is the threat to the US.