Why Didn’t Hitler Invade Switzerland in World War II?

A Test of Defensive Deterrence

Tyler Piteo-Tarpy
16 min readMar 29, 2022


Switzerland has acted as a neutral state since 1516, with the exception of the Napoleonic Wars between 1798 and 1815. At the Congress of Vienna on November 20, 1815, Austria, Britain, France, Portugal, Prussia, and Russia all agreed to recognize Swiss neutrality,¹ a commitment that has endured despite the two world wars since then.

In this paper, I will examine how, even in the face of Nazi Germany’s expansionist aggression, the Swiss maintained their independence. I will test the hypothesis that it is precisely Switzerland’s neutrality — and the defensive doctrine it entails — that was able to “both deter and reassure”² Hitler, causing him to tolerate this small free state in the middle of his European empire. I will also analyze the alternative explanation that Swiss economic collaboration with the Nazis disinclined them from invading, though they could have done so had they wished to, to assess its plausibility.

Ultimately, I conclude that the Germans were motivated to invade, but that Swiss policy increased the risk enough that, at a time in the war when the Germans couldn’t afford the potential costs, they were deterred from going through with their plans.


Because the international system consists of actors who view the world through different lenses (motivated or cognitive biases and theories) and are perceiving and reacting to each other, it is very difficult for anyone to be certain of anyone else’s true intentions. This uncertainty is problematic when making policy in response to other states because choosing a policy that doesn’t match what is really going on can lead to unintentional escalations of threats.

For example, if a state starts preparing for war due to a fear for its security, and in response, other states threaten retaliation, then this policy will only confirm the nervous state’s fears and prove to it the necessity of a defensive war. On the other hand, if expansionism motivates the mobilizing state, a policy of negotiation and appeasement designed to quell security concerns will merely make it easier for the aggressive state to attack. The lessons learned from the two world wars demonstrate this problem, as due to the belief that the First could have been avoided by negotiation and appeasement the Second was not prevented by a strong deterrence.

After laying out these problems in the chapter “Perceiving and Coping with Threat,” political scientist Robert Jervis points out that the solution is “to develop policies that can both deter and reassure, that can communicate that the state will resist encroachments on its vital interests but has no desire to challenge the vital interests of the other.”³ A state that can communicate defensive capabilities and peaceful intentions in such a way that is believable to others should theoretically be safer from attacks motivated by either insecurity or expansionism, and what such a policy looks like is, in my estimation, what Switzerland achieves through its neutrality. In his book Neutralization and World Politics, historian Cyril Black gives this definition of a neutral, or “neutralized,” state:

A neutralized state is one whose political independence and territorial integrity are guaranteed permanently by a collective agreement of great powers, subject to the conditions that the neutralized state will not take up arms against another state, except to defend itself, and will not assume treaty obligations which may compromise its neutralized status.⁴

Within this definition are the fundamentals of deterrence and reassurance; the former from the qualification of armed defense, and the latter from the conditions against military intervention abroad. Additionally, the collective agreement stipulation addresses the problem of ambiguity and misperception as multiple states agree to hold the same benign interpretation of the neutral state, thus creating trust.

What holds these factors together though is the nature of the neutral state’s military. It would possibly be in keeping with the above definition for a threatened neutral state to fight offensively for its national defense. However, maintaining and developing an offense-capable military always has the potential to threaten others, which could create a spiral of distrust that leads to an arms race and war. Thus, for a state intent on keeping its outward perception as benign as possible, its military should be defense-oriented. “Elevating ‘deterrence by denial’ in US defense strategy,” an article by the Atlantic Council, notes that:

Historically, deterrence has come in two forms: punishment and denial… Denial strategies, adds Michael J. Mazarr, “seek to deter an action by making it infeasible or unlikely to succeed.” These strategies work when a country… shores up its own defenses to such an extent that offensive operations are perceived to be inordinately costly for an attacking country.⁵

A non-threatening national defense reassures the neutral state’s neighbors that it couldn’t attack them even if it wanted to, and deters the neutral state’s enemies by making invasion impractical for all but the most extreme political goals.

In the next section, I will discuss what specific policies and tactics Switzerland used to achieve this defensive deterrence. More broadly, I will look for confirming and disconfirming evidence that Switzerland’s defensive military, geographic, and diplomatic stance gave it the ability to both “deter and reassure” Hitler; communicating both that an invasion would be too costly for Germany and that an independent Switzerland had no intention of causing trouble.


The best evidence for defensive deterrence would show that the Germans had an interest in taking Switzerland, evaluated their chances of success, and in the end, decided invasion would be too costly to justify. The strongest evidence against this theory would show that there was little interest in invading, even though there was a high chance of success. My hypothesis then depends on what the Germans knew and thought about Switzerland.

Confirming Evidence of Interest:

SS reports on public opinion after the armistice with France on June 22, 1940, indicate that there was popular support and advocacy for war with Switzerland. “The demand repeatedly surfaces that “Switzerland has yet to be swallowed,” that “Switzerland may not be overlooked in the reorganization of Europe.””⁶ Even if the SS exaggerated or fabricated these reports, they would still indicate that the German leadership they were meant for was looking for support for a war. Goebbels and Hitler, for example, expressed the same feelings, the former even writing of the latter that “the Fuhrer rails against the neutrals. The smaller, the nastier. They must not survive this war.”⁷ Hitler also reportedly referred to the Swiss as ““a pimple on the face of Europe” which “cannot be allowed to continue.””⁸

Moreover, Switzerland was long seen by the nationalistic Germans as an aberration, with its people having multiple national origins and speaking multiple languages. “By the late 1930s, Nazi cartographers were proactively including German-speaking Swiss cantons in their maps of Grossdeutschland,”⁹ indicating the desire and intention of carving up Switzerland to fit their vision of the world. Finally, the Nazi’s goal of exterminating all Jews also extended to neutral states, as indicated in the account of the Wannsee-Konferenz which listed the number of Jews the Germans hoped to kill in Switzerland, necessarily after an invasion.¹⁰

Prior to the armistice, there was also a strong incentive to use Switzerland as another route into France, outflanking the Maginot Line. German planners talked about this option as early as 1931, which included going “through Belgium and the Netherlands in the north”¹¹ as well, both also neutral states.¹² Notably, Germany did use the northern portion of this plan, but not the southern portion. Switzerland and France, however, were so worried about this possibility that they formed an agreement to allow French troops into Switzerland should Germany invade, and the French even refused to reinforce their northern defenses from the south after the invasion of Belgium.¹³

Furthermore, fighting occurred in early June as German planes violated Swiss airspace. After Swiss pilots shot down several planes, the Germans tried to sabotage Swiss airfields, but the Swiss uncovered the plot before it succeeded. The situation caused by these incidents was so precarious that the Swiss reluctantly apologized and returned what pilots and planes they could to conciliate the Germans.¹⁴ However, the Germans gained another potential justification for war when they discovered documents detailing the secret French-Swiss defensive agreement, and, as France was retreating, Hitler ordered planning for an invasion to begin.¹⁵

Disconfirming Evidence of Interest:

In the 1990s, there was a revival of investigations into Swiss collaboration with the Nazis that led to discoveries or confirmations about, for example, secret Swiss bank accounts containing assets belonging to Holocaust victims, “the purchase of Nazi gold by Swiss banks, Switzerland’s role as a hub for stolen art, and its cooperation with secret intelligence services… as well as the refusal to admit Jewish refugees into the country.”¹⁶ In 1996, the Swiss government created an Independent Commission of Experts (ICE) consisting of international historians to come to official conclusions about Switzerland’s role in WW2 which confirmed these findings, also noting that Switzerland violated its neutrality in granting loans to Germany and Italy.¹⁷

Additionally, Switzerland traded with both the Allied and Axis powers, including in arms — which went mostly to Germany once it had surrounded Switzerland, though the Swiss imported about five times as much weaponry and war material as they exported.¹⁸ This trade was necessary not just to disincentivize invasion, but also to feed and employ the Swiss people. “There are statements from the Nazi camp that Switzerland was indispensable to the German economic war effort, in particular its financing assistance. That dependency was reciprocal, for the Swiss could not have survived without German supplies.”¹⁹

This evidence points to a symbiotic relationship where both sides needed the other, though to different extents. Switzerland couldn’t afford to cut off all contact with Germany, thus their policies reassured Hitler that they would work with him, not against him. On the other hand, Hitler needed foreign exchange aid in the first stage of WWII that he got from the Swiss.²⁰ However, in light of the confirming evidence of interest, this mutual reliance doesn’t hold up as reason enough to prevent invasion.

In his paper “German Plans and Policies regarding Neutral Nations in World War II with Special Reference to Switzerland,” historian Gerhard Weinberg points out that “whatever damage occurred in the country during a German invasion… would hurt the Swiss themselves, not the Germans; and the assets of the country would swiftly fall into German hands.”²¹ Perhaps if the Germans were apathetic to the future of Switzerland they might have considered it too much trouble to take the country and its wealth by force when they were already getting it through trade. But because of the incentives to redraw the map of Europe as they saw fit, eliminate the embarrassing neutral island in their empire, kill the Swiss Jews, and get revenge for Swiss air victories and secret alliances, I would judge the interest to weigh on the side of invasion, especially when it would pose practically no cost to their finances, the only cost being military. On this part of the test of defensive deterrence then, I believe the theory holds up.

Chance of Success:

After the Germans occupied France and gained access to Switzerland’s western border, an invasion became more promising as the Swiss had previously focused their defenses on the German border and now faced the enemy from all sides, forcing them to split their forces along multiple fronts. On June 24, 1940, Hitler discussed the possibility with his generals and officials; notably, “Foreign Minister Ribbentrop favored an immediate occupation of Switzerland, while General Keitel was of the opinion that German goals could be reached… “without risking the sacrifice of some hundred thousand German soldiers.””²² This estimation is significant because in the war against Belgium, Germany suffered only 61,000 casualties,²³ and Belgium’s population was twice that of Switzerland’s.²⁴ ²⁵ Against France, a country with ten times the population of Switzerland,²⁶ Germany only suffered 156,000 casualties.²⁷ The mention of 100,000 possible casualties then indicates a recognition that the Swiss had a strong defense for a country its size, especially as the politician advocated for invasion while the general was against it. Furthermore, what suggests that this number wasn’t a purposeful exaggeration is that in the Winter War, the Finns, with an army half the size of Switzerland’s, dealt an estimated 1,000,000 casualties to the Soviets.²⁸ ²⁹ Compared to that, 100,000 seems conservative.

The Swiss, like the Finns, were known for their sharpshooting, and every man was issued a rifle from conscription into the national militia.³⁰ To best take advantage of this strength, Swiss strategy held that “at the moment of German invasion, the Simplon and St. Gotthard tunnels would be blown up, as well as all bridges over the Rhine, power stations, and air fields. Avalanches and landslides would be set off to block armor and infantry movement,”³¹ thereby controlling the German advance and making them easier targets.

Despite Keitel’s opposition, Hitler deployed Army Group C along the Swiss border with France to await the order to invade. On June 25, a plan was submitted to the Army High Command that called for a surprise attack from France, Germany, and Italy to quickly overwhelm the Swiss before they could retreat further into the Alps.³² Known as the Swiss National Redoubt, this strategic retreat was ultimately seen by both the Swiss and Germans as “the only possible defensive solution” where “reinforced and well guarded natural obstacles would win out over armored and motorized vehicles.”³³ These natural obstacles were complemented by fortifications for artillery, machine gun nests, tank traps, and tunnels for troops to hide and quarter in, leading the Germans to refer to Switzerland in song as a “porcupine.”³⁴

However, until August, “a half demobilized and unmotivated army was spread out on the plateau,”³⁵ unwisely set to defend their full territory, thus spreading themselves beyond their porcupine’s limits. Historian Klaus Urner believes that at this point “the German general staff had clearly recognized the weaknesses of the Swiss defense plans” and “at no other time during World War II would a German-only surprise attack have had such disastrous effects.”³⁶ This ideal moment of Swiss weakness and an ideal plan to take advantage of it was paired with “Hitler’s fits of rage against Switzerland;”³⁷ it is strange then that he didn’t give the order, as a more opportune moment would not present itself. It could be that even in such a situation the risk of getting bogged down and sustaining unacceptable losses was still seen as too high, at least while there was still conflict within France and with Britain. Or it could be that the espoused interest and build-up to invasion was just posturing without ever any real intent, perhaps to frighten Switzerland into collaborating. But if the latter was the case, then a lot of time, effort, and “rage” was spent on posturing, much of it in secret, with Hitler’s own generals and officials, no less.

In the following months, Germany kept up troop movements along the border and kept preparing new war plans.³⁸ Historian Georges-Andr Chevallaz notes that the redoubt did have a “deterrent effect”³⁹ and that the general staffs were trying to dissuade Hitler from acting on his hatred of Switzerland. On August 26, General Halder drew up another plan with the knowledge that “Switzerland is determined to resist any invasion by exerting all her strength.”⁴⁰ On this point, another deterrent tactic the Swiss government used was to order their soldiers to regard any message of surrender as enemy propaganda and to ignore it, thus producing a tied-hand effect that ensured continuous resistance, even if Germany took most of the country.⁴¹ In contrast, France surrendered to the German blitzkrieg in a little over a month.⁴² German intelligence also reported in September that Swiss morale had increased since the fall of France as England held out against German air raids.

Even still, General Leeb of Army Group C drafted yet another plan, this one called Operation Tannenbaum. In a review of Tannenbaum on October 9, the general staff decided to cut the proposed twenty-one divisions down to eleven, though Italian forces would also participate. This cut in the allotted forces presents another challenge to the theory of defensive deterrence, as it implies the Germans weren’t worried about underestimating the Swiss, though at least part of the rationale was that they could not maintain the element of surprise with such a large force.⁴³ At the same time, and unaware of Tannenbaum, General Zimmerman drafted a second plan that stated “no operation in the Alps!”⁴⁴ which could also help explain the shrinking of the invasion force. If a prolonged siege of the redoubt was out of the question, then Germany’s only chance was to win decisively before the Swiss could retreat. The reduced German force was still larger and stronger than the Swiss army, but it prioritized speed over swamping the whole country with soldiers.

By December, Hitler had decided to attack the Soviet Union, shifting his focus away from Switzerland.⁴⁵ For about five months there was a real threat of invasion, but it was never fulfilled. Weinberg writes that:

All in the German government took it for granted that Germany would control Switzerland after winning the war… While the fighting was still under way, Switzerland could serve German purposes by permitting the transit of goods through the Alp-tunnels, by laundering stolen gold and other valuables, by providing important munitions and electricity, and by a substantial range of other services. Once the war had been won, the country could be overrun quickly.⁴⁶

And historian Regula Ludi agrees that “only the Allied liberation of Europe prevented Switzerland from eventually becoming incorporated into the Third Reich.”⁴⁷ Even the German song likening Switzerland to a porcupine follows with “we will take her as dessert; then we’ll go to the wide world and get us Roosevelt.”⁴⁸ While I believe my analysis has shown that actually Switzerland would be difficult to overrun, the rest of what I found is consistent with these conclusions. The chance of success for Germany was low for what it wanted at the time, that being a quick and easy occupation. I don’t doubt the Germans, with twenty times the population, could have eventually taken Switzerland, especially after they’d beaten all their real threats; but the Swiss army, judged by the German Captain von Menges to be “suitable only for defensive purposes,”⁴⁹ was, it seems, able to deter invasion at the time when it counted, and hold out until the Allied victory.


Because Nazi Germany was an expansionist state, appeasement was not successful for the Allies before the war. Because the Germans had an interest in taking Switzerland during the war, appeasement would not have been successful for the Swiss. Therefore, it stands to reason that Germany should have invaded if it weren’t for a compelling deterrent. Switzerland’s military strategy and perilous geography were able to make invasion just difficult enough that Hitler kept putting it off to focus on larger threats and targets. Importantly, Switzerland’s neutrality and defensive military posture convinced Hitler that it didn’t pose a threat to Germany, and Switzerland’s economic collaboration ensured it wasn’t viewed as an immediate or essential target, thus it placated the Germans while they waited for a more opportune moment to attack, a moment that never came. The Swiss example should be a lesson for those small states throughout the world that worry about the predations of their larger neighbors. Armed neutrality, defensive deterrence, and fighting spirit have the potential to carry these states over the line from an easy snack to a porcupine.


  1. Gordon E Sherman, “The Neutrality of Switzerland.” The American Journal of International Law 12, no. 2 (1918): 241–50. https://doi.org/10.2307/2188141.
  2. Robert Jervis et al., “Perceiving and Coping with Threat,” in Psychology and Deterrence (Baltimore, MD: Johns Hopkins University Press, 1991), pp. 13–33, 33.
  3. Jervis, “Perceiving and Coping with Threat,” 33.
  4. Cyril E. Black et al., Neutralization and World Politics (Princeton: Princeton University Press, 1968), xi, quoted in Matthew Schandler, “The Economics of Neutrality: Switzerland and the United States in World War II.” Thesis, (Louisiana State University, 2005), 7.
  5. Erica D. Borghard, Benjamin Jensen, and Mark Montgomery, “Elevating ‘Deterrence by Denial’ in US Defense Strategy,” Atlantic Council (Forward Defense, February 19, 2021), https://www.atlanticcouncil.org/content-series/seizing-the-advantage/elevating-deterrence-by-denial-in-us-defense-strategy/.
  6. Klaus Urner, Ge N. Alexander M.Haig, Let’s swallow Switzerland! : Hitler’s plans against the Swiss Confederation, (United Kingdom: Lexington Books, 2001), 16.
  7. Ibid., 17.
  8. Walter Olson, “Target Switzerland: Swiss Armed Neutrality in World War II,” (Reason, October 1998).
  9. Ibid.
  10. Gerhard L. Weinberg, “German Plans and Policies Regarding Neutral Nations in World War II with Special Reference to Switzerland.” German Studies Review 22, no. 1 (1999): 100.
  11. Edgar Ansel Mowrer, “The Swiss Rearmament,” Foreign Affairs 14 (July 1936): 620.
  12. Herbert R. Reginbogin, Faces of neutrality : a comparative analysis of the neutrality of Switzerland and other neutral nations during WWII, (Germany: International Specialized Book Service Incorporated, 2009), 28.
  13. Neville Wylie. Review of “Life between the Volcanoes.” Switzerland during the Second World War, by Pierre-Th. Braunschweig et al., The Historical Journal 38, no. 3 (1995): 760–61, http://www.jstor.org/stable/2640018.
  14. Georges André Chevallaz, The challenge of neutrality : diplomacy and the defense of Switzerland, (United Kingdom: Lexington Books, 2001), 21.
  15. Stephen Halbrook, “Blitzkrieg 1940,” in The Swiss and the Nazis: How the Alpine Republic Survived in the Shadow of the Third Reich, (United States: Casemate Publishers (Ignition), 2006), page numbers not available.
  16. Sara Ormes, “A Masterable Past? Swiss Historical Memory of World War II.” Senior Honors Theses. 4. (The University of New Orleans, 2011), 42–43. https://scholarworks.uno.edu/honors_theses/4
  17. Ibid., 44–47.
  18. Dietrich Schindler, “Neutrality and Morality: Developments in Switzerland and in the International Community,” American University International Law Review 14, no. 1 (1998): 159–160.
  19. Detlev F. Vagts, “Switzerland, International Law and World War II,” American Journal of International Law 91, no. 3 (1997): 469. doi:10.2307/2954183.
  20. Weinberg, “German Plans and Policies,” 100.
  21. Ibid., 102.
  22. Halbrook, “Blitzkrieg 1940,” page numbers not available.
  23. “Battle of Belgium (May 10–28, 1940) Summary & Facts,” Totally History, December 19, 2013, https://totallyhistory.com/battle-of-belgium/.
  24. C. Peter Chen, “Switzerland in World War II,” WW2DB, accessed March 9, 2022, https://ww2db.com/country/switzerland.
  25. C. Peter Chen, “Belgium in World War II,” WW2DB, accessed March 9, 2022, https://ww2db.com/country/belgium.
  26. C. Peter Chen, “France in World War II,” WW2DB, accessed March 9, 2022, https://ww2db.com/country/france.
  27. C. Peter Chen, “Invasion of France and the Low Countries,” WW2DB, accessed March 9, 2022, https://ww2db.com/battle_spec.php?battle_id=32.
  28. Stephen Halbrook, “Switzerland Is a Porcupine,” in The Swiss and the Nazis: How the Alpine Republic Survived in the Shadow of the Third Reich, (United States: Casemate Publishers (Ignition), 2006), page numbers not available.
  29. Morgan Bell, “The Winter War,” WW2DB, accessed March 10, 2022, https://ww2db.com/battle_spec.php?battle_id=30.
  30. Ibid.
  31. Olson, “Target Switzerland.”
  32. Halbrook, “Blitzkrieg 1940,” page numbers not available.
  33. Chevallaz, The challenge of neutrality, 69.
  34. Halbrook, “Switzerland Is a Porcupine,” page numbers not available.
  35. Chevallaz, The challenge of neutrality, 73.
  36. Urner, Let’s swallow Switzerland!, 6.
  37. Ibid., 42.
  38. Halbrook, “Blitzkrieg 1940,” page numbers not available.
  39. Chevallaz, The challenge of neutrality, 192.
  40. Halbrook, “Blitzkrieg 1940,” page numbers not available.
  41. Urs Schwarz, The Eye Of The Hurricane: Switzerland In World War Two, (United Kingdom: Taylor & Francis, 2019), page numbers not available.
  42. Chen, “Invasion of France and the Low Countries.”
  43. Halbrook, “Blitzkrieg 1940,” page numbers not available.
  44. Ibid.
  45. Reginbogin, Faces of neutrality, 17.
  46. Weinberg, “German Plans and Policies,” 100, 102.
  47. Regula Ludi. “What Is So Special about Switzerland?” In The Politics of Memory in Postwar Europe, edited by Claudio Fogu, Richard Ned Lebow, Wulf Kansteiner, 210–248, (United Kingdom: Duke University Press, 2006), 218.
  48. Halbrook, “Switzerland Is a Porcupine,” page numbers not available.
  49. Halbrook, “Blitzkrieg 1940,” page numbers not available.



Tyler Piteo-Tarpy

Essayist, poet, screenwriter, and comer upper of weird ideas. My main focus will be on politics and philosophy but when I get bored, I’ll write something else.