Comment by FridayoLeary

You missed an important point which is that Switzerland under the guise of neutrality helped the germans finance the war. For most of the time it very much was not in Germanys interest to invade. If their track record is anything to go by, if they had it probably wouldn't have taken them very long. Very few military lessons can be learned from the Swiss for the simple reason they have never fought in a war. As a Brit i'm obligated to point out that it's a similar story with France because they have never won a war.