Their are tens of thousands of US troops that are not active duty who would gladly go over as mercenaries. As someone has to do if pay for the travel and equipment and you’d have a rdy made army without “US boots on the ground”. Most people know that obama would frag them in a heart beat and only a brave few have been willing to dive into the mess.
However if the government clearly the way and put the iraqi kurds in charge of it then isis would be dealt with in months.... possible weeks.
Once again isis’s biggest ally is obama. He gave them most of the gear they have and he’s protected them from both US and iraqi kurd forces.
This is our president telling ISIS, "DO NOT RISK YOUR LIFE"