The trans-atlantic link is responsible for that and the US has actively campaigned to keep it that way.
It boggles the mind that the EU Member states think an EU Common Foreign and Security Policy worth its name, and a proper European Defence Agency, are a threat to their sovereignty, but that NATO where they do what the US says is not. We have met the enemy, and he is us — Pogo
NATO exists. NATO works. Why change something that works and replace it with something that might not? Peak oil is not an energy crisis. It is a liquid fuel crisis.
