Extremism in the Middle East isn't on a president. It's not like as if the US had kept a remedial force in Iraq that somehow it would be all raindrops and lollipops and McDonalds on every street corner there.
That is an ideology, and really all that would've done is probably incite a never ending spate of attacks against US soldiers in the Middle East.
It's a damned if you do/damned if you don't scenario, if you're there, then everyone piles on and says you're imperialist and get the troops out they're getting killed in attacks, etc. etc. If you don't intervene then people say you're responsible for creating a vacuum.
I hate to say but maybe people in the Middle East need to rise up and realize extremist religious ideology has never brought anything good to the region. Until that happens no outside force can be a solution, the people there have to want it and understand that secularism is good.
You can only take a horse to the water, you can't make it drink.
Also the average American kinda needs to understand ... not every freaking thing revolves around them either. ISIS exists largely because a geopolitcal civil war going on in the Middle East between the Sunnis (largely financed by Saudi Arabia, Qatar, and others) and Shia (largely financed by Iran and Syria). That's the main reason it gained power.
