Peter Kassig's death is an individual tragedy - an act of almost baffling brutality.
However, it does not surprise security officials here in the US.
The President, who will be back in the White House from the G20 summit in a few hours, will meet with his advisers, trying to assess how the war with Islamic State is going: are these airstrikes proving effective?
Perhaps the greatest single concern to security officials are reports from the Middle East that the fractured jihadi groups in the region are now beginning to show a united front.
That would clearly pose a very potent threat both to Europe and to the United States.