The army tank is no good in mountainous country. I once had a friend from Belgium, and I used to chide him for the Belgian capitulation to the German invasion in World War II. Belgium is flat country, facilitating the movement of troops and tanks. Switzerland, on the other hand, has the Alps, plus a warrior mindset since the time of Caesar.
Yes, the Alps. They are still uncovering the airplane hangars, the hospitals, the barracks the Swiss had built into those formidable peaks, in preparation for a German invasion. Airplane hangars? Yes, the Swiss Messerschmidts (they bought those from their potential enemy) took off from mountain roads to shoot down enemy planes (though the Alpine fortress was almost immune).
Have you ever noticed how the Lord provides defensive abilities to Nature’s vulnerable? The rabbit and the deer are known for their swiftness. And so the Swiss, with no numerically superior force, have still that brazen sense of military bravado, which you see in action in the Holy Land. (The IDF is modeled on the Swiss army.)