Eventually we will sue for peace, or try to find a way out of this mess
You can't sue for peace with ISIS, they are not interested in it!
What we are trying to do now is find a way out of the mess and the bombing will be a very small (but necessary) part of it. If the bombing is simply a delaying tactic which just slows down the spread of ISIS, it will have served its purpose.
Whilst we try to contain them miitarily, other tactics can be deployed; economic, diplomatic, religious, cyber etc etc but anything that can be done NOW to degrade their capabilities must be done.