Peter Kenez’s fine Liberty Forum essay accurately captures the historical and political sense of the Ribbentrop-Molotov Pact. I would like to emphasize two points that supplement his analysis: Russia’s role in the outbreak of the Second World War, and the tragic plight of Poland.
…there is no doubt that the war started when Hitler and Stalin decided to act together against Poland: the Ribbentrop-Molotov agreement was almost immediately followed, as Professor Kenez points out, by Germany’s invading Poland on September 1, and Russia’s doing the same two weeks later. The fact that Russia, being later attacked by Germany, had to change sides and helped to defeat Hitler does not diminish her disgraceful role in the outbreak of the conflict.
Poland preferred to fight, fought bravely, and lost terribly. Looking back at the history of the countries that did not oppose Hitler—such as France or Hungary, which suffered much less than Poland—one might come to a not very uplifting conclusion that sometimes being honorable in politics does not pay.