A German and a Soviet officer shaking hands at the end of the Invasion of Poland.
"A German and a Soviet officer shaking hands at the end of the Invasion of Poland." (source)

On the 17th of September 1939 the Soviet Union invaded Poland from the east, following a German invasion from the west which started 2 weeks prior.

It's taken for a fact in Poland that at the time Soviets and Nazis were allies, per secret protocols of the Ribbentrop-Molotov Pact.

treaty included a secret protocol that divided territories of Romania, Poland, Lithuania, Latvia, Estonia and Finland into Nazi and Soviet "spheres of influence", anticipating potential "territorial and political rearrangements" of these countries (Wikipedia)

On the other hand for example in the US many people believe that Soviets and Nazis were always enemies (you can find such a claims for example in comments to Did the USSR have 21 thousand tanks at the beginning of WW2?).

Were Soviets and Nazis de facto allies in September 1939?

Related: Was Stalin planning to attack Germany?

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    The term "de facto ally" is perhaps unclear: if two powers are intending to fight each other in the future, can they be "allies" in the present? Is there a 'notable claim' that they were de facto allies (because reading the whole of published claim can help to clarify the meaning/context of the claim)? Do answers need to say what the Soviet motive was for invading Poland?
    – ChrisW
    Commented Sep 18, 2013 at 9:18
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    "allies" could imply a range of cooperation from joint military action to lesser agreements to not attack each other or to trade. If cooperation existed for some period, even if it was reversed later, then it doesn't seem unreasonable to describe the parties as allies, though it might help to specify the domains of the allegiance.
    – matt_black
    Commented Sep 18, 2013 at 10:36
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    @ChrisW: true, however not relevant. Also Soviets were very much officially part of the Allies. The "Big Three" were Stalin, Roosevelt and Churchill.
    – vartec
    Commented Sep 18, 2013 at 13:16
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    This shouldn't be on Skeptics. We have a whole site for historical questions which has many history experts. You are much more likely to get good answers there. Commented Sep 17, 2018 at 16:57
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    What exactly is the problem? Are you skeptic about the existence of the Ribbentrop-Molotov Pact (including secret parts)? Seems to me like there is strong historical consensus. Perhaps it would be better to challenge the contradicting US views you have spoken about, as long as you can find notable claims thereof.
    – Scrontch
    Commented Sep 19, 2018 at 12:00

2 Answers 2


Churchill (who was of course partisan) alleged that they weren't exactly cooperating: from http://www.ibiblio.org/pha/policy/1939/1939-10-01a.html

"Russia has pursued a cold policy of self-interest. We could have wished that the Russian Armies should be standing on their present line as the friends and allies of Poland, instead of as invaders. But that the Russian Armies should stand on this line was clearly necessary for the safety of Russia against the Nazi menace.

At any rate the line is there, and an Eastern Front has been created which Nazi Germany does not dare assail. When Herr von Ribbentrop [German Foreign Minister] was summoned to Moscow last week, it was to learn the fact, and to accept the fact, that the Nazi designs upon the Baltic states and upon the Ukraine must come to a dead stop.

I cannot forecast to you the action of Russia. It is a [riddle] wrapped in mystery inside an enigma; but perhaps there is a key. That key is Russian national interest."

On the other hand, Wikipedia's article on The secret protocol of the Molotov–Ribbentrop Pact says,

With the Western nations unwilling to accede to Soviet demands, Stalin instead entered a secret Nazi–Soviet alliance.[77]

In summary the answer seems to me to depend on what you think "de facto ally" means.

The section titled Expansion of raw materials and military trading seems to me to meet at least the second definition of "ally", and quite possible the first as well:

  • noun: a state formally cooperating with another for a military or other purpose, typically by treaty.
    antonyms: enemy, opponent
    a group of nations taking military action together, in particular the countries that fought with the US in World War I and World War II.
  • verb: combine or unite a resource or commodity with (another) for mutual benefit.

On the other hand, per for example Churchill's view, they were also "opponents".

It's possible that the Soviets were "reluctant allies" (for example, if I were cooperate with you because you had a gun to my head, I'm uncertain whether that would make me your "ally").

Various points of view are discussed in Wikipedia's Post-war commentary regarding the motives of Stalin and Hitler.

Several possible motives are alleged, including:

  • In return for 'non-intervention' Stalin secured a breathing space of immunity from German attack
  • The claim that the Soviet Union was at the time threatened by Hitler, as Stalin supposed,...is a legend, to whose creators Stalin himself belonged
  • Stalin's primary motive for signing the Soviet–German non-aggression treaty was his calculation that such a pact could result in a conflict between the capitalist countries of Western Europe
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    Churchill, as every other Western commentator, didn't have full view at the time, given that secret protocols were in fact secret and it's existence was denied by Stalin. I'd much rather take more recent opinion of historians having access to the documents.
    – vartec
    Commented Sep 18, 2013 at 10:06
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    @vartec what is the recent opinion? Commented Sep 18, 2018 at 22:06

Molotov-Ribbentrop Pact merely involves partitioning of Poland.

If that pact is considered an alliance, then what is generally sanitized as "Munich" or "Munich Conference" in Anglosphere would also constitute an alliance in between Britain and Germany, since it was about partitioning Czechoslovakia without even letting Czechoslovaks a chair at the conference table. Britain itself did not take any part of the country, but it gave approval to that partition and guaranteed non aggression against Germany due to the partition. But Anglo literature never calls it 'Munich Treaty' or 'Munich Pact' or 'Munich Alliance'; it is always called 'Munich', as if it was a rock concert or sports meet. At the time Britain (tories) were doing everything in their power to prevent any alliance against Germany in between France, Poland, Czechoslovakia and USSR, and even went to the extent of protesting when such an alliance potential appeared, saying "Germans will fear you are surrounding them!" and proceeded to prevent any alliance by individually going from country to country to diplomatically sabotage it. It was not so much a secret that Britain and its establishment (especially industrialists) wanted to use Germany against the rising threat of Soviet Union, lest it would empower social and economical demands of the people within Britain. (minimum wage, better working conditions, weekend vacation, 8 hour workday, retirement, social security etc).

This phenomenon is explained splendidly in one of small lectures of historian Michael Parenti, including circumstances leading to this situation:



Molotov-Ribbentrop pact was signed at the backdrop of this diplomatic scene, after all attempts of USSR for arranging any alliance against Germany was thwarted. On top of that, there were the territories Poland took from USSR during the civil war, and Soviets wanted those territories back. The final factor for the signing of the pact was Stalin's intent to delay a war in between USSR and Germany at whatever cost in order to give USSR time to prepare (no one doubted Germans would eventually want a war since they came to power in Germany by chanting "Death to communists" over one decade), and also put a buffer in between USSR and Germany in the form of Poland's territory.

Most important thing to notice is that its interestingly signed right after who was going to win the Battle of Khalkhin Gol in between USSR and Japan became clear, and under what conditions.

Khalkhin Gol affair easily explains what was the position of these two countries against each other - im going to quote from my answer on a relevant subject on Quora:

Battle of Khalkhin Gol as USSR vs Japanese starts in east asia at 11 May. The date is important, so please pay attention to it.


Anti-Comintern Pact


Anti Comintern pact was a pact signed in between Fascist countries against 'Communist enemies'. That practically being USSR. Japan was one of the axis countries and was in anti comintern pact. It was a pact made explicitly against communist countries. That being USSR at the time.So there is no way in hell german staff did not know about what was about to transpire in Khalkhin Gol.

Japanese said the battle was because of a rogue general taking initiative and initiating the conflict and Tokyo didn't have a hand in it, but thats total bull - during 4 months Tokyo could have ordered their general to stop or removed him. They didnt.

This means that this explanation is just an excuse japan government used to test USSR before engaging in a full scale war. So we can easily say that Nazis knew about Khalkhin Gol beforehand, and the test was not only for Japan's ambitions, it was also a test of anti-Comintern against USSR.

Things get interesting after this point; Khalkhin Gol lasts 4 months - and Molotov-Ribbentropp pact is signed on august 23.


You can easily guess that by august, the rate Khalkin Gol battle was going was evident - since 20 august was the date Zhukov started Soviets' final attack which moped up the Japanese and ended the war. So signing of Molotov-Ribbentrop pact is AFTER the final soviet offensive starts in khalkin gol, at which point there was no mistaking who won the confrontation and with what kind of result. Basically soviets overran japanese, actually using the very tactics and strategies they were going to use in beating the Nazis.

To summarize;

  • USSR and Germany could not have been allies by any legality, because USSR and Germany were already enemies due to Anti-Comintern pact.

  • Khalkhin Gol affair and Molotov-Ribbentrop pact's signing overlap - pact is signed only after it was evident that Soviets were going to win an overwhelming victory in Khalkhin Gol battle. Japan tested Soviets on behalf of anti-comintern pact, and they were found quite strong. And a direct offensive against USSR seeming impractical at that point in time.

  • It was a given that by attacking Poland, Germany would confront UK and France in actual war. Having USSR uncooperative, nervous or even hostile was not a good prospect. Thus, the incentive for some kind of neutrality.

  • Both parties had historical claims to various Polish land, USSR had a particular vengeance coming from 1919 invasion Poles did all the way to Ukraine with French support. Hence more incentive for the affair.

  • Neither Germany nor USSR could let the other take over Poland uncontested. It would be strategically dangerous, and also they would lose their claims to the lands they claimed. Therefore both sides needed to act. The best way to do this without risking conflict would be an agreement.

Therefore, we can easily say that there was no point in time in which these parties even felt as allies, leave aside actually being allies, and this affair was as it seems - an uneasy postponing of hostilities and resolution of a problem in which both parties had a stake in.

Nazis came to power by claiming to be defending 'western civilization against communism', and used the excuse of 'preventing communism from spreading' to sell their actions to the west in a lot of the annexations and moves they did in central Europe. They had the 'untermensch' label for the Slavs, they were in need of massive industrial resources, oil, manpower. They couldn't let an uncontested USSR build up their industry and military in their eastern border, which would have been suicide in their quest of dominating their 'lebensraum' - aka Europe.

Nazis knew this. Soviets knew this. Both sides knew that they were eventually going to go to war, and Soviets were preparing silently for it, keeping their preparations in the west to a minimum in order to not risk provoking Germans to a preemptive attack, whereas Germans were openly building for it.

The pact was just a postponing of the ultimate and inevitable conflict for convenience, and history has shown it to have been so.

Incidentally, almost every major European country had treaties with Nazi Germany, as can be seen in the below list. All of those treaties just go 'unmentioned' like 'Munich' when talking about the period.

enter image description here

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    All good and sound on a strategic level, but it doesn't contradict the fact that Nazis and USSR were allies for the operations in Poland, September 1939. See en.wikipedia.org/wiki/… . They even held joint victory parades!
    – Scrontch
    Commented Sep 19, 2018 at 12:20
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    @Scrontch the parade you are refering to is not a victory parade but a German parade diring the transfer of Brest-Litovsk from Germany to the USSR. It was dedicated to transfer of power, not to victory. "Look how we are strong but we depart and leave the city to you".
    – Anixx
    Commented Sep 22, 2018 at 17:07
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    @unity100 you're factually wrong, in that the German-Soviet alliance went way beyond a non-aggression pact. There were agreements to jointly attack Poland, economic cooperation, joint military exercises.
    – jwenting
    Commented Sep 25, 2018 at 4:30
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    Additionally, a non aggression pact is always an indicator of hostility in between states: US and UK have fought against each other numerous times in the past 200 years, yet not once needed to sign a non aggression pact. Same with France and UK. It is accepted that these countries wont attack each other unprovoked and with intent of destroying each other. Hence no need for any such pact. Whenever a non aggression pact is signed, it is always in between hostile countries who are existential threats to each other.
    – unity100
    Commented Sep 25, 2018 at 16:33
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    @IMil Well, there are patriots everywhere who will excuse anything, but what has this to do with historical accuracy? Just because some Russians want to whitewash the MR pact, does not mean that the other pacts become something different right? I mean, Poland got a territorial gain from the Munich pact but lost territory due to the MR pact. However, where I went to school (Germany), Poland was presented as a quite "innocent" country which was divided between the Germans and the Soviets. The Munich pact got presented in a much more neutral light that the MR pact.
    – Andrei Kh
    Commented Oct 23, 2019 at 16:41

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