Season 15, Episode 14: The Tripartite Pact
While the Export Control Act put in place by the US government in 1940 specifically did not include oil embargoes, it became clear within the span of the first few months of 1941 that the Empire of Japan was determined to continue its war against China as well as its recent invasion of French Indochina regardless of threats from the United States. However, in order to understand the US’s decision to finally cut off oil supplies in the summer of 1941, we must take a slight step back to discuss other developments in Europe during the (sigh) second World War.
In late 1939, Nazi Germany’s invasion of Poland resulted in a de facto state of war between them and the UK. Attentive listeners might wonder why a similar state of war did not emerge between the UK and the Soviet Union, who invaded Poland a week after Nazi Germany. The answer lies in the delicate balance of diplomacy and posturing which existed at the time.
Nazi Germany’s justification for its invasion of Poland revolved around the Free City of Danzig, which is located on the Baltic Coast in Poland’s north. Like many cities in border regions, Danzig had a long and complex history which involved being at times part of Poland and at other times part of the contemporary German state. During the 1930s, the majority of Danzig spoke German and identified as Germans and thus, by Hitler’s reasoning, they should be German citizens and Danzig should belong to Germany. However, the Free City of Danzig was just that - a free citystate which was under the protection of the League of Nations. Throughout the late thirties, however, Nazi Germany had been making overtures for Poland to agree to their intention to annex Danzig, which Poland had been refusing. On September 1, 1939, the army of Nazi Germany invaded and proved far too agile, quick, and adaptable for the Polish attempts at defense. While the tactics employed by the Germans during this invasion are sometimes referred to as their first blitzkrieg, or “lightning war” offensive, military historians remain divided on whether it actually counts.
German troops were given Pervitin, a form of methamphetamine which allowed them to stay awake for days at a time and overrun their Polish counterparts faster than the defenders could react. While Germany’s just cause was the forced annexation of Danzig, the Soviet Union’s stated purpose was the defense of eastern Poland from Nazi aggression.
By the time the USSR rolled tanks and troops into eastern Poland, the German invaders had already made short work of the Polish army. Rapid offensives, overwhelming artillery, and a numerical advantage of around two to one all served to establish German superiority in the field with such rapidity that the Soviet Union declared the Polish government effectively defunct and claimed that they were forced to invade the eastern portions of the country to preserve a buffer between themselves and the Nazi aggressors.
There is no question that the UK was obligated by their Anglo-Polish Alliance Treaty to declare war on Nazi Germany, but a secret provision in the treaty specified that they would only help preserve Polish territory specifically from a German invasion. Having no desireto immediately launch a war against two sovereign neighbors and, indeed, not being strictly required to, the UK declared war against Germany and publicly condemned their invasion as naked aggression.
France had also entered into an alliance with Poland but that agreement would prove even less effective than Poland’s pact with the UK. While France had been allied to Poland since the end of the first World War, a new agreement was reached in 1939 in which both nations pledged to assist the other in the case of war against Germany. The Commander of the French Army, General Maurice Gamelin, even promised to launch an energetic offensive within three weeks of Germany’s then-theoretical invasion of Poland. The new treaty was actually ratified just a few days after Germany’s invasion and France, staying true to its word on paper, launched what is now called the Saar Offensive. This retaliatory assault against Nazi Germany was, however, a far cry from what Poland believed the French had promised.
Having declared war against Germany a few days after the invasion of Poland, the French Army on September 7 launched an offensive against Saarland, a German state which lies along France’s northern border with Germany near Luxembourg. The target was the Siegried Line, a fortified defensive line which Germany had established to defend against invasion from France. The original plan called for forty army divisions along with dozens of supporting battalions and regiments, particularly artillery and armor, to launch a major attack on Saarland which would overrun the Siegfried Line. When it came time for actual deployment, only eleven divisions were activated along with some minimal supporting artillery and tanks.
This was still a rather significant mobilization, even if it was less than a quarter of the size originally planned. In fact, France had chosen the best possible moment to strike Germany - most of their armed forces were committed to the invasion of Poland in the east and those remaining who held the Siegfried Line were extremely sparse. Even in its reduced state, those participating in the Saar Offensive on behalf of France outnumbered their immediate opponents by a ratio of three to one, which even in a modern war can be extremely significant.
French forces crossed the border into Saarland and quickly seized control of a sizable chunk of its southern area - around seven square kilometers, a little over two and a half square miles. However, this seizure was not exactly the triumphant victory which French High Command had hoped for. Aggressive German counterattacks, anti-tank mines, and poor intelligence conspired against this offensive. Although the French possessed numerical superiority, they remained uncertain of the enemy’s strength and thus after two weeks of defending the German soil they managed to hold, they failed to even reach the Siegfried Line, much less punch through it. In late September, the decision was made by General Maurice Gamelin to withdraw French troops back to their own defensive line. By this point, organized defenses of Poland itself had been largely crushed by German and Russian invaders and there seemed little point to continue fighting on behalf of allies who had been conquered. A contingent of French Generals opposed this decision, arguing that France had an opportunity to gain an advantage over her old foe Germany while she still possessed the initiative, but as the withdrawal stretched into October the German defenders were being actively replenished by their comrades who were returning from conquered western Poland. Just as Germany had built a fortified defensive line to guard against their western neighbors, so had France constructed its own set of defensive fortifications near their German border.
The Maginot Line, named for French Member of Parliament Andre Maginot who conceived of it and argued for its creation, stretched along the eastern border of France which it shared with Italy, Germany, and Belgium. When Belgium objected to France constructing concrete fortifications along their shared border, France conceded and only fortified the German and Italian frontiers. The Maginot Line served multiple purposes for the government of France: it required fewer active-duty soldiers which allowed them to control army expenditures, it comforted the people that the threat of invasion from Germany was basically impossible, and it could be used for counter-offensives in the extremely unlikely scenario of a German invasion. It was the perfect defense against a repeat of the first world war.
However, like much French military philosophy of the twenties and thirties, the Maginot Line was not an invulnerable, impenetrable defensive line but actually just another relic of the first world war. Although the concrete bunkers were invulnerable to aerial bombing and tank bombardment, France’s defenses around the rest of the country were paltry and outdated. The Germany which they faced in 1914 was a completely different nation from the one they had just declared war upon. The grind of trench warfare was about to be replaced by rapid advances supported by armor and mobile artillery. It’s also worth noting that the German incursion into France during the first World War came not along their shared border, but through Belgium.
However, though Hitler might have wanted to launch an all-out war against France, his forces needed time to recover. The conquest and annexation of western Poland had ended swiftly but it still cost lives and money. His five-year plan proposed total German autarky by 1940 and achieving that was still a long way off.
The dramatic invasion of Poland was followed by an eight-month period which was dubbed “The Phoney War.” During these eight months, there was very little military activity from either side, with France busily mobilizing but uncertain about what to do next and the UK in the midst of a political crisis as Prime Minister Neville Chamberlain’s efforts to prevent another large-scale European war had not only failed, but emboldened the enemy they now faced.
For the Soviet Union, however, the invasion of eastern Poland provided an opportunity to settle some old scores. The Baltic States of Estonia, Latvia, and Lithuania all signed mutual assistance treaties with the USSR which allowed the latter to station Soviet troops in those countries. Finland, a Scandinavian nation which shares a long, porous border with Russia, had been part of the Russian Empire and had experienced a tumultuous relationship with the Soviet Union since the revolution. Finland occupied several disputed territories which Stalin asserted should belong to the Soviet Union. He sent Vyacheslav Molotov to negotiate for them but negotiations quickly broke down. In late November of 1939, a border guard post in the Russian village of Mainilsky was shelled by artillery. Stalin accused the Finns of aggression, which they denied. In fact, there was no Finnish artillery within range of the village and it was revealed years later that this was a false flag attack staged by the Red Army to give a just cause for Russia to invade, conquer, and annex Finland once and for all.
The ensuing three-month conflict, dubbed “The Winter War,” did not proceed as the Soviet Union believed it would. The Finnish army prepared several defensive lines and employed a strategy of delaying the Russian onslaught rather than trying to match it on equal terms. Guerrilla tactics were a favorite of the Finns, whose white overcoats rendered them nearly invisible against the endless white snow. Platoons would ski cross-country across difficult terrain and take action behind enemy lines, disrupting the Soviet supply lines. The primary advantage which the Soviet Union possessed, however, was tanks. The Finns had very little in the way of anti-tank weaponry but their need for improvisation produced one of the most famous incendiary weapons in world history: the Molotov Cocktail.
The weapon, which is simply a bottle filled with flammable liquid topped with a burning fuse - usually a cloth - was jokingly called “a cocktail for Vyacheslav Molotov,” hence the still-used name of Molotov Cocktail. It proved a frustrating difficulty for Soviet tank crews, whose olive-green tanks proved an easy target for incendiaries and a variety of simpler forms of sabotage like jamming logs into the exposed gears which controlled its treads. As a result, about 80 Soviet tanks were destroyed during the three-month war.
While the invasion proved more difficult than Soviet high command had anticipated, the Red Army did manage to make some headway. In early December, Finnish defenders withdrew from their forward positions to the Mannerheim Line, their primary fortified line of defense. Guerrilla units continued operations behind enemy lines, often successfully isolating and even encircling groups of Soviet soldiers who had become separated from their main army. The Winter of 1939 and 40 was particularly brutal, and the temperature plunged as low as negative forty-three degrees Fahrenheit, which is negative forty-one point six degrees celcius, very near the negative forty degrees which is the same measure in both systems.
After three months of brutal fighting with little to show for it, both sides sat down in early March of 1940 to hash out a peace agreement. The outcome of this war is sometimes counted as a victory for Finland, though the ensuing Moscow Peace Treaty which ended hostilities did include larger land concessions to Russia than what the Soviets had demanded before the war. The UK and France diplomatically supported Finland, as did most of the League of Nations, which expelled the USSR for their aggression, but that support did not materialize in war supplies in the way the Finnish government had hoped. All that being said, it’s hard to justify categorizing the conflict as a win for Russia, given that their armed forces in the region outnumbered the Finns by about two to one and yet they were unable to force a decisive battle and lost somewhere in the neighborhood of a hundred fifty thousand troops, some of which were battlefield casualties but a significant number of which died of exposure, frostbite, or some other natural cause brought on by the severe winter.
The humiliation of the Soviet Union in the Winter War inspired a reassessment of their military prowess among the higher echelons of Nazi Germany, who were still waiting for the UK and France to do something in response to their invasion of Poland besides the paltry Saar Offensive which had already been driven back to France. Seeing that their enemies had thus far been reluctant to actually commit armed forces to battle in spite of the fact that they had both declared war, German High Command decided to bring the eight-month “Phoney War” to an end.
On April 8, 1940, the German army invaded Norway, seizing control of the port city of Narvik after two days of brutal fighting. On the 9 of April, the German army simultaneously invaded Denmark, violating the non-aggression pact they had previously signed with that country. Although Danish scouts had observed a mass concentration of German troops along their border with Germany, the Danish government worried that mobilizing their own armed forces would be seen as a provocation and give the Nazis a just cause for invasion. This was part of the reason why, when Germany did invade Denmark, they were able to complete their conquest in about six hours. Yes, you heard that right; it took six hours for Denmark to capitulate to Nazi invasion and be annexed by Germany. The quick surrender meant that much of Denmark was still intact - they did not experience the destruction of a bombing campaign similar to what the Nazis had inflicted upon Warsaw some months before.
Norway would not be as lucky. The Nazi campaign to conquer their northern neighbor would succeed after a destructive and devastating two-month struggle. Sweden would not face a German invasion and managed, through a combination of diplomacy, assurances of neutrality, and cooperation, to avoid the fate of their Scandinavian neighbors.
On May 10, 1940, while the conquest of Norway was still underway, Nazi high command decided that the time was right to correct the mistakes of the first world war and invade not only the low countries - Holland and Belgium - but also take France. Because the border with France was fortified on the French side by the Maginot line, Nazi leadership opted to push quickly through Holland and Belgium to invade from the north, bypassing the concrete bunkers on France’s eastern border.
During the first world war, Germany’s invasion of Belgium proved to be a costly mistake - it made them an international pariah and their army was tied up for a month suppressing Belgian resistance, giving France the time it needed to mobilize an adequate defense. This time, things would turn out very differently.
Invading with mixed units in which armor, air power, and infantry were all coordinated, on May 10, 1940, a massive German army breached Holland and Belgium: Holland surrendered after a week of fighting and Belgium surrendered a little over two weeks after the initial incursion. While that invasion was still ongoing, German troops pressed through Belgium into France from its northern border, attacking at Sedan on May 12. Sedan held great historical significance for both Germany and France; after winning a significant victory there in the Franco-Prussian War of 1870, France surrendered to Prussia and the German Empire was born.
This time around, the Germans won the Battle of Sedan in three days, taking advantage of faulty French intelligence which had posited that the area was, for tanks, completely impassable. This proved not to be the case. The loss of Sedan dealt an incredible blow to French morale; the parallel to their humiliating defeat in the Franco-Prussian War was on the mind of every French soldier and citizen. The French army performed just as poorly in subsequent battles and proved incapable of matching the Germans for speed, maneuver, and coordination. On June 10, 1940, just a month after the German invasion began, Paris had been captured.
On June 16, French Prime Minister Paul Reynaud resigned from office after his cabinet thoroughly rejected his desperate proposal to merge the French and British governments into a Franco-British Union to avert looming defeat. He was replaced as PM by Philippe Petain, a Marshal in the French army who had gained significant fame due to his effective defense against the German offensive at Verdun during the first world war. The new Premier announced via radio address that he intended to plead with Germany for an armistice, which Hitler was delighted to entertain on certain symbolic conditions. The ensuing negotiations took place in the exact same location and in the same exact train car as the negotiations for armistice during the first world war, when it was Germany who was pleading for a peaceful conclusion. The ensuing agreement ceded much of occupied France to Germany, chiefly the north and west of the country, while preserving the southeast as an independent government under French control. With the backing of the rump parliament, Petain used emergency powers to form an entirely new government for the new state of France, establishing the new capital in the city of Vichy, which is why France in this period is referred to as Vichy France.
The French people were outraged at Petain’s apparent power grab but domestically there was little to be done. Some French military forces who were deployed at overseas colonies rallied against Vichy France and proclaimed Petain a despicable traitor. These forces would eventually coalesce under the leadership of General Charles de Gaulle, whom we will discuss more in a future episode.
Throughout the summer of 1940, Germany took to the skies and attempted to inflict as much damage as possible on the UK. For three months, from July to October, the skies over the English Channel and throughout much of southern Britain were alight with massive air battles and bombing raids nearly every night. The government of the UK had experienced some turnover since the invasion of Norway in May. Neville Chamberlain resigned and Winston Churchill was the new Prime Minister. He formed a coalition government with the express aim of forcefully prosecuting the war against Germany and winning. The primary objective of the Germans during the three-month Battle of Britain was to convince the UK to make peace. Plans were drawn up for an amphibious landing of southern England but in spite of the aggressive air campaign, the British navy was still firmly in control of the channel and these plans were eventually scrapped.
Japanese leaders looked at European chaos as an opportunity. The east Asian French colony of Indochina, whose territory corresponds roughly to the modern nations of Vietnam, Laos and Cambodia, had been allowing supplies to flow freely through their own territory into China, effectively supplying the Empire of Japan’s enemies. Throughout the summer of 1940, in the confusion of the armistice and establishment of the Vichy government, Japanese military leaders eventually lost patience with the governor of French Indochina, who repeatedly rebuffed their requests to halt shipments to China, and invaded the colony. The governments of both nations had been negotiating a settlement wherein Japanese inspectors would be allowed to police shipments traveling through French Indochina, but the Imperial Japanese Army arranged for an invasion to launch in late September of 1940, yet another example of the dual governments of Japan working at cross purposes. The fighting lasted for four days until civilian forces were able to communicate that the Vichy government had bowed to their demands. Japan was allowed to militarily occupy the northern part of the colony, called Tonkin, and were allowed to control shipments traveling to China.
Although it was signed shortly after the invasion of French Indochina, the Tripartite Pact had been months in the making. On September 27, 1940, the document was a formal declaration of alliance between Nazi Germany, Fascist Italy, and the Empire of Japan. The document itself is a near-perfect example of diplomatic crybullying, as it opens by declaring that (quote) “Italy, Germany and Japan will henceforth conduct in common and jointly a war which has been imposed on them by the United States of America and England.” (end quote) Japan insisted on including the United States, who was still making their war effort extremely difficult with the Export Control Act which greatly limited Japan’s access to vital warmaking materials.
Fighting in China continued in stalemate, though the Japanese at home had been assured by the state-controlled media that the whole affair was nothing but Imperial victories all the way down. After a few short-lived Prime Ministers came and went, usually resigning after failing to bring the war with China to a satisfactory conclusion, Konoe Fumimaro once again succeeded to the premiership. His second term would be shorter than his first, but no less consequential. He formed the Taisei Yokusankai, or “Imperial Rule Assistance Association,” which was originally meant as a political reform group but rapidly evolved into a single political party bent on establishing permanent one-party rule in Japan, with mixed results. A few years later, all elected members of the Diet would be required to join this group, regardless of personal desire.
While Germany and the Soviet Union had hashed out a secret agreement to jointly invade Poland and respect one another’s spheres of influence, this diplomatic tolerance was far from a budding friendship. Hitler’s success at knocking down European countries one at a time was giving him a dangerous amount of confidence and even Stalin was beginning to worry that he would soon decide to invade Russia. Although Soviet and Mongolian troops had triumphed over Japanese forces in the Battles of Khalkin Gol a few years earlier, neither was eager for a full-scale war with the other. In the spring of 1941, the Soviet-Japanese Neutrality Pact was signed by representatives of both parties, each guaranteeing the other that they wouldn’t be attacked, even if the other party was at a state of war with one of their allies.
Some of the fallout from this treaty would land on the Chinese as the Soviets ceased all weapons and aid shipments to mainland China. With the Japanese increasingly interfering with the Republic of China’s ability to receive such weapons and aid from overseas partners, this sudden severance with goods coming from Russia was a terrible blow to their continuing war effort. Chinese communists were in an especially awkward position, since Stalin was supposed to be their particular ally and he had seemingly thrown them to the wolves.
The summer of 1941 was a volatile period in geopolitical developments; the Nazis were busily consolidating their gains and trying to keep the pressure against the UK while also mounting a full-scale invasion of Russia; the Japanese, now that they were occupying Tonkin, were seemingly positioning themselves to directly surround the Philippine Archipelago. While the US government had declared an embargo against a wide-ranging list of war materiel being sold to Japan, they had refused to cease selling oil to the Japanese because they believed this would be too provocative. In August of 1941, however, President Franklin Roosevelt decided that enough was enough; if Japan wanted to continue making war in east Asia, it would do so without American oil.
The ensuing oil embargo was a huge blow to the Empire of Japan, who had been importing nearly all of their oil from the US. Now they would be reliant upon only the stockpile they had so far purchased, which put extreme pressure on the Imperial military to bring a swift end to the war in China or risk losing that war entirely. In late 1941, the decision was made to punish the US for their continued support of Japan’s enemies and hopefully knock them out of the war before they had a chance to enter with their full strength.
Next time, we will discuss the German invasion of Russia as well as the surprise attack on Pearl Harbor, which brought the United States kicking and screaming into the global struggle of the second World War.