My opinion: we are seeing medieval barbarians behave like medieval barbarians....and should do everything in our power to destroy them and prevent their spread into civilization.
It's not our problem. Think about the French or the Japanese sending troops to Ferguson to clean up injustice that Americans can't deal with.
This is a regional problem that needs to be addressed by those in the region. It's not the job of America to right every wrong in the world.
As for Foley, he met his death with some dignity, no crying or whimpering or begging for mercy which means he showed more bravery and character than most people would in the same circumstances. His bravery though wasn't total. He submitted to his death, he didn't fight, he denounced his brother and country. He was emotionally vanquished and allowed himself to be used as a pawn. Why? He was brave enough to die with dignity so why did he permit them to have power over him to lead him to submit and denounce? This brought shame onto him in the last moments of his life.
He gave his executioners power and glory. Not glory by western standards but glory within the realm of Islam. These men are fighting to bring change to that region, horrible as the change is. That has to be acknowledged. For the followers of Islam, especially the young disaffected men, this execution video will be a powerful statement. A Muslim has broken a Western man, made him submit to his own death and had him renounce family and country.This paints the West as weak and Islam as strong.
In the end, Foley was like Rachel Corrie, a misguided liberal
interfering in affairs that weren't his and he paid the price for his meddlesome nature.