What can you possibly do...

What can you possibly do ... to deter people like this?  The only plausible solutions are those that kill them.  The lefties like to call that war-mongering, and the libertarians like to call it interventionism.  Neither has any believable alternative, just variations on themes for delaying the inevitable confrontation. If history has taught us anything at all (a thoroughly debatable proposition, that), it has taught us that all such delays increase the cost in both blood and treasure – and immeasurably increase the risks...