While the odds were against any sort of meaningful Swiss victory in the event of invasion, such a German offensive was equally unlikely in the early years of the war. By 1943, the possibility of a successful German invasion had dwindled to virtually nothing, as the Swiss Army had expanded and modernized to a point that would make Tannenbaum a suicidal mission. This begs the question: why, then, would Hitler ever have chosen to invade Switzerland? Let us proceed with our counterfactual under the following premises.
It is now September 15. The unrestricted bombing campaign authorized by Churchill four months ago has been relatively unsuccessful. Fewer than 25 percent of the bombs dropped are landing within five miles of their intended targets, and only 30 percent have landed in any built-up areas. However, this has had an unintended benefit. Having disguised the few industrial plants manufacturing jewel bearings, the Germans were fairly certain of their security. However, in a truly ironic case, this ended up being more costly, as the plants have been disproportionately hit by the British bombs. Jewel bearings are a main component of bombsights, and without them, Hitler is reluctant to press his luck in the Battle of Britain, much less Operation Sealion.
The other use for jewel bearings is in wristwatches. The Swiss were, of course, masters of watch-making. Since the victory in France and near-total encirclement of Switzerland, the Germans had successfully coerced the export of a large number of these jewel bearings, and in fact, except for those few plants in Germany, Switzerland was the exclusive manufacturer of them. The situation calls for action.
Bern sees the leverage it has in such a commodity, but is reluctant to press its luck against an already belligerent Führer. Berlin is desperate for a replacement source for the jewel bearings; as losses in the Battle of Britain have already amounted to over 400 aircraft.
The Swiss are taking their own toll on the Luftwaffe. Since May 1, eight planes have been either destroyed or forced to land by the Swiss Air Force and their German- and French-designed Bf-109s and D-3800s. The Nazis have responded with tersely worded notes, warning that “the German Reich reserves the right to take any measures necessary for the prevention of attacks of this nature … In event of any repetition of such incidents, the Reich will dispense with written communications and resort to other means of safeguarding German interests.” However, it will be in response to the Axis encirclement of Switzerland, and not the German diplomatic protests, that General Guisan ordered the immediate cessation of hostile action against German aircraft.
The Swiss continue to fly combat air patrols, but with direct orders not to engage. The presence of both German and Swiss fighters of the airspace of the latter was an accident waiting to happen. OKH has been tinkering with their plans for Fall Grün – Case Green – the invasion of Switzerland.
On September 17, the VIII Fliegerkorps under Luftflotte 4 was reassigned from Deauville, France to an airfield in just outside Baden in Austria. For the next several days, the pilots will conduct various air patrols to familiarize themselves with the new terrain. For many men, though, this is entirely unnecessary, as the VIII is stocked with former pilots of the Austrian Bundesluftwaffe.
There are some who do need the training – not only are they strangers to the new area, but they fresh pilots, only several months out of their Lehrdivisions (training division). The various Jagdgeschwader (JG) are stationed all across Austria and southern Germany, with JG 54 just north of the Black Forest.
September 21 dawned grim and overcast in Bern and across the country – foreboding weather. Despite the weather, Leutnant Emil Jurgen of the Schweizer Luftwaffe is engaged in a routine patrol somewhere over the Jura. Jurgen is with the 9 Fliegerkompanie based in Avenches, and gets separated from his wingman in the heavy cloud cover. At the same time, a unit of German Bf-109Es from the 54th J.G. is conducting their own patrol, led by a veteran of the Battle of France, Hauptmann Max Rankle. As the Germans fly though the clouds, the leftmost pilot, Leutnant Rolf Schüler, spots a plane. It isn’t one of theirs.
Schüler has only had his wings for six weeks now. Spotting a Morane-Saulnier exiting the clouds ahead, Schüler thinks back to the silhouette identification chart he diligently hung above his bunk. He then remembers why the outline looks familiar – it’s a French plane!
He opens fire, but it is sporadic and off-target. Jurgen sees the fire and pulls his D-3800 into a sharp climb, while he banks to his left. Below him is the perfect target; Schüler is silhouetted against the clouds, and with a precisely-aimed burst, Jurgen sets the right engine aflame and sends Schüler’s plane spiraling towards the ground.
Upon hearing of the encounter, Federal President Pilet-Golaz broadcasts a heartfelt apology that evening. “This pilot,” he promised, “will suffer the severest consequences permissible. Switzerland has always been a nation predicated on the rule of law, and nothing has been done to change that.” Hitler is not persuaded.
With the Luftwaffe unable to maintain a production schedule with their lack of jewel bearings, he has found his new pretense for invading another neutral country. In a radio address to the German people, he denounces the “barbaric aggression” of one “piddling nation,” which “thinks it can dictate to the German people their rights.” Promising a swift campaign, Hitler orders OKH to execute Fall Grün, which has not been reduced in size from the 12th Army version of the plan; 17 divisions are to be committed. After (very) brief consideration, he decides to not consult Mussolini, assuming that when the Germans are nearing victory, he’ll invade on his own initiative.
Guisan immediately orders the full mobilization of the Swiss Army, effective as of midnight on September 22. The border guards are at full alert, and by 0600, the entire 800,000 man army is at their posts.
In a speech to his general staff, portions of which are broadcast on the radio, Guisan issues a stern rebuke to the German invaders: “For eight hundred years, we Swiss have persevered through the worst conflicts to ravage Europe. We have kept to ourselves, wishing to harm to any nation or peoples. But if you so much as set one foot across our borders, we will defend them to the last man. There will be no surrender from us.” To his officers, he says “now is the test of our national character. Our spirits are high, and we will win the day.” For his conclusion, Guisan switches to his heavily-accented German and, in a play on the Third Reich slogan, declares that “Wir sind nicht ein Volk, sondern Vielen. Wir sind nicht ein Reich, sondern viele Staaten. Wir haben keine Führer – wir haben jeder Mensch. Wir sind jetzt die Verteidiger der Freiheit im Europa und Welt! Wir werden niemals Verzicht!”
At 0200 on Tuesday, September 24, a massive artillery barrage and intense heavy bombing of the border defenses begins. The 7th Grenzwache (border guard) battalion, many of whom are from the Landsturm reserve, is nearly wiped out in the Thurgau area. The rest escape relatively unharmed. In accordance with Fall Grün, the first wave of Fallschirmjäger is dropped into Bern and the St. Maurice region at 0300. At 0415, German troops cross the Swiss border at Geneva and in the Vaud, Basel, Neuchâtel, Aargau, Zürich, and Thurgau cantons.
Resistance is heaviest in the north, where 3 battalions of border guards are backed by two infantry divisions. The entire German XXV Corps enters there, along with two infantry divisions of the XXVII Corps. In the northeast, three German divisions have been committed against three battalions and a division. Geneva falls in hours. Three Fallschirmjäger battalions dropped into the Olten area are met by the Motorized Liebstandarte SS-Adolf Hitler Brigade at 0530.
In Solothurn on the outskirts of Bern, where much of the industry (and particularly those jewel bearing plants) is, the citizenry has holed up in their homes. Most have weapons. However, Guisan has miscalculated. The traditional assumption was always that if the Germans chose to invade, it would be in order to the secure the mountain passes in the south. Thus, according to plan, the bulk of the Swiss Army fights a retreat back to the Alps. The primary goal of 12th Army is to secure industrial strongpoints. Even so, Fall Grün calls for swift action to secure the alpine transit routes, and this remains unchanged during the military operations.
The manufacturing plants in Zurich and Solothurn remain relatively untouched. Maurice St. Germain, an industrialist, manages to torch his Zeitmesser Fabrikat plant before he retreats to his country home in the Valais canton. The 1st Gebirgsjäger Division splits, sending half its men to Aarberg and the other half to Biel. The Motorized SS-Großdeutschland division is sent from the rear to hold Solothurn, and the various forces in Olten and Solothurn advance on Bern. Legend will have it that the capital falls at, in military time, 1648 – the year of Switzerland’s independence from the Holy Roman Empire – but regardless of the exact time, by 1700 Bern is in German hands.
Following the same strategy used by their predecessors in Belgium a generation earlier, Leeb opts to bypass and invest the few Swiss strongholds in the lowlands. The major cities are all taken by Day 2 of the invasion, the 3rd Light Brigade in Zurich having held out for thirteen hours longer than any other. A direct assault by the 260th Infantry Division, coupled with the two battalions of Fallschirmjäger that had dropped into Wegen on the Walensee put an end to the siege.
In total, the ‘Advanced Position’ outlined in Op. Bef. 12 had fallen even sooner than expected, and the Germans were closing in on the National Redoubt with three entire Army Corps a day ahead of schedule.
The first (and only, really) Swiss offensive is towards Geneva. The 20th Motorized Division, a part of the reserve force, has advanced to that city to assist the 52nd Infantry Division with occupation duty.
The 42,000 French and Polish soldiers interned, including the entire Polish 2nd Rifle Division, are rearmed with the great stockpiles of arms the Swiss have been preparing, and together with the Swiss 1st Light Infantry division and remnants of the 1st Grenzwache they march on Geneva. The battle is fierce, and lasts over several days, but as soon as the two panzer divisions of Generaloberst Hoth’s XV Panzer Corps are committed, it is over for sure. The French surrender, as do most of the Poles, but the Swiss fight to the last man. There are 18,042 prisoners taken in the Second Battle of Geneva. Only 1,162 are Swiss.
In the south, the Germans were taking an interesting route. Hoth’s XV Corps was to travel from Geneva through demilitarized France and attach the Simplon Pass from the rear. From Geneva, the 4th and 8th Panzer Divisions split into a pincer movement, terminating at Brig. They were to be joined by several battalions of Fallschirmjäger.
Lying in wait for them, thought, were the 10th Brigade and 1st Division of the Swiss Army at the St. Maurice Fortress. They were armed with a complement of 5 120mm howitzers, 4 84mm guns, and numerous 53mm positions at Fort Savatan and 6 120mm, 2 75mm guns plus 53mm emplacements at Fort Dailly. When Hoth’s panzers reached them on October 2, they managed to repulse the Germans with massive casualties. After two more days of fighting, Hoth withdrew and regrouped. “Die Schweizer können zu ihren verdammt Berg halten,” he spat. He was a patient man. And he did not mind waiting.
Concluded in part 4 here.
 Richard Overy, Why the Allies Won (New York: W.W. Norton, 1997) 104.
 See Orson Welles’ famous line in The Third Man: “In Italy, for thirty years under the Borgias, they had warfare, terror, murder, and bloodshed, but they produced Michelangelo, Leonardo da Vinci, and the Renaissance. In Switzerland, they had brotherly love, they had five hundred years of democracy and peace – and what did they produce? The cuckoo clock.” Of course, the Swiss did not invent the cuckoo clock – the Germans did.
 Urner 88-90.
 Herren, “The Timeline 10.5.1940 – 30.11.1940,” Tannenbaum 1940; Halbrook, Target Switzerland 108.
 “We are not one people, but many. We are not one Reich, but many states. We have no Führer – we have all men. We are now the defenders of freedom in Europe and the world. We will never surrender!”
 Kaufmann and Jurga 157.
 “The Swiss can keep their damn mountain.”