Simply not worth the death or maiming of one more American.
Yes, let's just leave the Taliban and other savage jihadists in Afghanistan alone, so they can take control of the entire country and turn it into one giant terrorism training zone, funded by the virtually limitless profits realized from narco-trafficking—which, of course, will ultimately result in the death and maiming of countless more Americans.
Just a thought.
Sometimes peaceful co-existence with vicious animals is problematic...