Our survival depends on winning the war against Islamofascist terrorism.
Which has what to do with deploying US ground troops in an Iraqi civil war zone with no identifiable enemy and no identifiable mission other than handy target?
Or perhaps you are suggesting that, in order for the US to survive, we need to have ground troops patrolling in Pakistan, Syria, Palestine, Lebanon, Iran, Saudi Arabia, etc., all of which are active participants in the spread of Islamic terrorism.