Defense of Western Europe

I previously advocated the dissolution of NATO and re-militarization of Germany, so that Western European Nations would know that they have the obligation to protect themselves and that it is not the responsibility of the US.
A political associate replied as follows:
"What would be the cost-effectiveness of your proposed plan, vs status quo.
What would be the cost, to us, of the next WWII (when Iran or Russia or China invades Europe and England), vs maintaining the status quo?"
My response is:
By eliminating our involvement in NATO and our standing army in Germany, we leave the defense of those needing defense to their own efforts, which is another manifestation of self-reliance. In the process, we save money by reducing our military expenses for those present operations.
We should not be involved in the next world war, unless it affects us directly, such as an invasion to our homeland. If Western Europe, including England, do not wish to protect themselves against Russian or Chinese occupation, who are we to say that they should?
Look back at the European portion of World War II. Germany was never a direct threat to US life and liberty. It costs us several million men to protect future life and liberty of Western Europeans, who now move in a socialistic system. Presume for a minute that we had not been involved in the European aspect, and that Germany was able to take over all of Europe including Russia. Would it have been bad that we would then have to do business with a Germanic Union. In order to avoid being motivated by emotional positions unrelated to facts, remember that the sinking of convoys by German submarines was only an effort on their part to reduce European capability of resistance. The Germans were making no direct attempt at jeopardizing America.
Avoiding loss of another several million American soldiers in a third world war operation would be a cost-benefit and from a trade point of view, we might find it much easier to negotiate with a single Russian or Chinese Union.