The blade at the throat is way to dull and fragile. The few combat troops we have there are hampered by many factors in their host country communities, such as: supply lines dependent on Euro ports, airstrips and roads, 2/3's of the U.S. forces are support personnel, military families are trapped in the communities, and the forces' original commitment was to merely be a detaining mission for the Soviet juggernaut (some called them canon fodder).
In short, Mr. Hanson is more correct than he lets on in the loss of political practicality of keeping our troops in old Europe.
You make a good point. Our presence in Europe is largely symbolic. It makes Europeans feel secure. Take away that sense of security and they would begin sucking up to us the way they usually do when they want something bad. Right now we are getting nothing in return for our protection. Let them pay for it--with more amicable relations.