1. In Western Europe, the strategy won. In the early 80's there was a grave concern that Western Europe was indeed suddenly vulnerable. Thus began the build-up that brought the GLCM, the 600 ship navy, and major growth of both Army and Air Forces in Europe. If this build-up had not occurred, any war in Europe would have been over in roughly a week. This was because the US didn't have the air frames and ships to deliver a credible counter-force in less time. It was felt that the Soviets would need 7 days to move their forces into readiness while we could have a division or two .... and NO EQUIPMENT...across in the same time. We saw roughly the same thing in Gulf War I....weeks and weeks of transporting equipment. (In fact, a significant portion of the men and equipment needed for Gulf I was drawn from Europe.)
The forces are there now (much smaller forces) as a contribution to NATO and to have a place to rotate them in and out of the ME. Even that mission is declining. If I named the just the air bases that have closed in Europe in the past 20 years, you'd be amazed....RAF Fairford, RAF Upper Heyford, RAF Bentwaters, RAF Woodbury, RAF Bentwaters, Sembach AB, BitBurg AB, Rhein-Main AB, Hahn AB, Zweibrucken AB, Torrejon AB, one of the bases in Italy, Comiso AB, and Hellenikon AB. Every one of these (except Hellenikon) held a single wing (24 aircraft) and about 2000 people. European end strength used to be about 1,000,000. Now I'd guess it's more like 350-400,000.
2. In S. Korea there is a small force (about a division and a half) and two air wings. They serve as a trip wire that causes the N. Koreans to think twice about invading. If S. Korea were to be invaded, the US forces would contribute but end up falling back. They would serve their purpose of holding the North until we could me the rest of the force into place. It's basically the same strategy as before the Korean War except the US force is larger and remains on alert. Part of the reason that worked was that N Korea had a relatively primative land and air force. That's not so true today and folks really have their thinking caps on about this.
All of this begs the question of whether or not we should or would feel compelled to act if truces/treaties were broken.