Operation Tannenbaum - Military Preparations

Military Preparations

An increase in Swiss defense spending was approved, with a first installment of 15 million Swiss francs (out of a total multiyear budget of 100 million francs) to go towards modernization. With Hitler’s renunciation of the Treaty of Versailles in 1935, this spending jumped up to 90 million francs. The K31 became the standard-issue infantry rifle in 1933, and was superior to the German Kar98 in ease of use, accuracy, and weight. By the end of World War II, nearly 350,000 would be produced.

Switzerland has a unique form of generalship. In peacetime, there is no officer with a rank higher than that of Korpskommandant (3-star-general). However, in times of war and in 'need,' the Bundesversammlung elects a General to command the army and air force. On August 30, 1939, Henri Guisan was elected with 204 votes out of 227 cast. He immediately took charge of the situation.

The invasion of Poland by the Wehrmacht three days later at noon caused The United Kingdom to declare war on Germany at 12:10. Guisan called a general mobilization, and issued Operationsbefehl Nr. 1, the first of what was to be a series of evolving defensive plans. The first assigned the existing three army corps to the east, north, and west, with reserves in the center and south of the country. Guisan reported to the Federal Council on September 7 that by the moment of the British declaration of war, "our entire army had been in its operational positions for ten minutes." He also had his Chief of the General Staff increase the service eligibility age from 48 to 60 years old (men of these ages would form the rear-echelon Landsturm units), and ordered the formation of an entirely new army corps of 100,000 men.

Germany started planning the invasion of Switzerland on 25 June 1940, the day France surrendered. At this point the German Army in France consisted of three army groups with 2 million soldiers in 102 divisions. Switzerland and Liechtenstein were completely surrounded by Occupied France and the Axis Powers, and so Guisan issued Operationsbefehl Nr. 10, a complete overhaul of existing Swiss defensive plans. The St. Maurice and St. Gotthard Passes in the south and the Fortress Sargans in the northeast would serve as the defense line. The Alps would be their fortress. The Swiss 2nd, 3rd, and 4th Army Corps were to fight delaying actions at the border, while all who could retreated to the Alpine refuge known as the Réduit national. The population centers were, however, all located in the flat plains of the north. They would have to be left to the Germans in order for the rest to survive.

Hitler demanded to see plans for the invasion of Switzerland. Franz Halder, the head of OKH, recalled: "I was constantly hearing of outbursts of Hitler’s fury against Switzerland, which, given his mentality, might have led at any minute to military activities for the army." Captain Otto-Wilhelm Kurt von Menges in OKH submitted a draft plan for the invasion. Generaloberst Wilhelm Ritter von Leeb's Heeresgruppe ‘C’ (HGr. C), led by Generalleutnant Wilhelm List and 12th Army would conduct the attack. Leeb himself personally reconnoitered the terrain, studying the most promising invasion routes and paths of least resistance. Menges noted, in his plan, that Swiss resistance was unlikely and that a nonviolent Anschluss was the most likely result. With "the current political situation in Switzerland," he wrote, "it might accede to ultimatum demands in a peaceful manner, so that after a warlike border crossing a rapid transition to a peaceful invasion must be assured."

The plan continued to undergo revision until October, when 12th Army submitted its fourth draft, now called Operation Tannenbaum. The original plan called for 21 German divisions, but that figure was revised downwards to 11 by OKH. Halder himself had studied the border areas, and concluded that the "Jura frontier offers no favorable base for an attack. Switzerland rises, in successive waves of wood-covered terrain across the axis of an attack. The crossing points on the river Doubs and the border are few; the Swiss frontier position is strong." He decided on an infantry feint in the Jura in order to draw out the Swiss Army and then cut it off in the rear, as had been done in France. With the 11 German divisions and roughly 15 more Italian divisions prepared to enter from the south, the Swiss were looking at an invasion by somewhere between 300,000 and 500,000 men.

Hitler never gave the go-ahead, for reasons still uncertain today. Although the Wehrmacht feigned moves toward Switzerland in its offensives, it never attempted to invade. After D-Day, the operation was put on hold, and Switzerland remained neutral for the duration of the war.