highres_30018917 copy.jpgOn this day in 1939, the German Army invaded Poland. Operation Fall Weiß (Case White), as it was code-named, sent more than 60 German divisions storming into Poland. It came a day after the Gleiwitz incident, one part of Operation Himmler. The latter had German troops dressed in Polish uniforms attacking German emplacements along the border in order to give a casus belli. At Gleiwitz, for example, an SS unit so dressed attacked a German radio transmitter and then retreated, leaving behind dead bodies also dressed in Polish uniforms. The bodies–those of concentration camp inmates–were called Konserve, or “Canned Goods.”

Operation Himmler served as the official German pretext for the invasion of Poland. Needless to say, the invasion was actually long-planned, and came at the end of a whole series of aggressive moves by the Nazi government, including the remilitarization of the Rhine, the forced reunification of Austria–the Anschluss–and the absorption of Czechoslovakia (with the connivance of Britain and France). The British and French had finally drawn a line in the sand when Hitler turned to Poland, but it was a line drawn next to the Baltic Sea, where those western powers were essentially helpless.

Molotov signing, with Stalin behind him

The only power that might have intervened to back Germany down was the Soviet Union but on 1 September they were Hitler’s allies, not enemies. Perhaps Hitler’s greatest diplomatic triumph, the Molotov-Ribbentrop Pact of 23 August 1939, had rewritten the balance of power in Eastern Europe. Its public clauses were expressions of friendship and mutual defense against third party attacks. Its secret clauses handed the Baltic States to the USSR and split Poland between the two countries. Even though they were secret, the clauses danced around the issue in an oddly passive voice: “In the event of a territorial and political rearrangement in the areas belonging to the Baltic States (Finland, Estonia, Latvia, Lithuania), the northern boundary of Lithuania shall represent the boundary of the spheres of influence of Germany and U.S.S.R. In this connection the interest of Lithuania in the Vilna area is recognized by each party,” read the first secret clause. “In the event of a territorial and political rearrangement of the areas belonging to the Polish state, the spheres of influence of Germany and the U.S.S.R. shall be bounded approximately by the line of the rivers Narev, Vistula and San. The question of whether the interests of both parties make desirable the maintenance of an independent Polish States and how such a state should be bounded can only be definitely determined in the course of further political developments. In any event both Governments will resolve this question by means of a friendly agreement,” read the second. “In the event of”? What, was Poland going to slip in the shower and accidentally rearrange itself territorially? In any case, the Pact set up the invasion nicely for the Germans. It meant that they need not worry about Soviet intervention against them.

The invasion represented two experiments on the part of the Nazis. First, Hitler (as he had been for so long) continued pushing the western powers to see how much he could expand in Central Europe without them pushing back. He had taken Austria and Czechoslovakia with either little protest or active cooperation. Poland was obviously a much larger gamble as a full-scale military invasion. The second experiment was with something of a new form of warfare. The German Army had spent much of the interwar years arguing furiously about how to deal with the static mess that had been the Western Front. Unlike the French, who essentially decided on the pre-built trench system of the Maginot line, the Germans looked to mobility to break the stalemate. This was not universally loved within the German high command, but there was enough support that the Germans began creating divisions of tanks and mechanized infantry, supported by mobile artillery and ground attack aircraft. When the war started in September 1939, the number of those divisions was still relatively low but they served as the spearheads as the German Army launched itself into the Polish defenses. This operational method was not fully developed in Poland, nor was it truly a break from the past German practices. It was, in many ways, a great trial run of a German way of war that had existed since Frederick the Great and before, reinvented for mass industrial war.


The Poles, unfortunately for them, had played into the German hands (as the Soviets would two years later). Their defense pushed right up to the Polish border and aimed only to grudgingly give ground, while waiting for the British and French to come to their aid by attacking Germany in the west. That put an large number of Polish units into the Poznan salient along the western border, ripe for German plucking. Poland’s overall strategic situation was dire, but this disposition of forces was, to put it mildly, not optimal.

In any case, at 4:45 am on that day, the ancient German battleship Schleswig-Holstein opened fire on the Polish fortifications in Westerplatte and German units surged across the border from Prussia, northern Germany, and southern Germany. Twenty years earlier, the negotiators in Paris had been writing a treaty that they hoped would avert another catastrophe like the Great War. The sound of the guns on September 1 was a sign of their most signal failure.

Map from United States Military Academy Department of History.