The secret pact that ushered in World War II and changed Europe

Animated graphic showing photo of signatories and photo of Molotov–Ribbentrop Pact in Russian (© Keystone/Getty Images)
(State Dept./M. Gregory)

Some people today think of Nazi Germany and the Soviet Union as bitter World War II enemies. But August 23, 1939, showed that wasn’t always the case.

On August 23, 1939, the two countries signed the Nazi-Soviet Nonaggression Pact, agreeing not to take military action against each other for the next 10 years.

Soviet and German newspapers carried the news the day after it was signed. “However, from the very beginning there was well-founded suspicion that the Pact contained more than met the eye,” wrote editors of Lituanus, an English-language journal dedicated to Lithuanian and Baltic history.

It did. Unknown to the public until years later, that day the two parties also signed a “Secret Additional Protocol” attached to the nonaggression pact. Just under 150 words, this secret protocol divided eastern Europe into Nazi German and Soviet “spheres of influence.” Specifically it:

  • Divided Poland along the Narew, Vistula and San rivers, with the Soviets controlling east of that line.
  • Paved the way for the Soviet Union to invade Finland and annex the Baltic states of Estonia, Latvia and Lithuania.
  • Opened the door for Bessarabia to be separated from Romania and annexed to the Soviet sphere.

Even today, except for Poland and the Baltic states, “the pact remains largely unknown,” writes British historian Roger Moorhouse in his book The Devil’s Alliance, which contains the full text of the pact and its secret additional protocol.

Adolf Hitler, at right, with arm outstretched toward rows of people in uniform below him (© AP Images)
Adolf Hitler, front, salutes parading troops of the German Wehrmacht in Warsaw, Poland, on October 5, 1939, after the German invasion. (© AP Images)

The pact gave Adolf Hitler a free hand to attack Poland without fear of Soviet intervention.

Hitler’s invasion of Poland just nine days after the pact was signed, on September 1, 1939, prompted Great Britain and France to declare war on Nazi Germany. On September 17, 1939, the Soviets invaded Poland from the east, occupying that part of Poland allotted to them by the secret protocol. This marked the beginning of World War II, the deadliest and most destructive war in history that involved more than 50 nations and deployed more than 100 million soldiers.

Following the Soviet invasion of Poland, in the spring of 1940, the Soviet secret police killed nearly 22,000 Polish prisoners of war and political prisoners in the Katyn Forest near Smolensk in the Soviet Union.

“It is clear that the Nazi-Soviet Pact turned the political world upside down,” Moorhouse wrote.

Although the pact ended in June 1941 when Nazi Germany invaded the Soviet Union, Moorhouse estimated 75 million people in central and eastern Europe felt its consequences and “huge numbers suffered persecution, torture and death at Soviet hands.” Today’s map of eastern and central Europe “is largely its product.”

The secret pact is part of an agreement sometimes called the Molotov-Ribbentrop Pact, named after the leaders who signed it: Nazi German Foreign Minister Joachim von Ribbentrop and Soviet Foreign Minister Vyacheslav Molotov, although Molotov went to his grave in 1986 denying the existence of the secret portion.

Fifty years later, on August 23, 1989, residents of Soviet-occupied Estonia, Latvia and Lithuania marked the day with one of history’s largest peaceful protests. Today, the date is recognized as Black Ribbon Day, or European Day of Remembrance for Victims of Stalinism and Nazism. It has expanded to include all those who suffer or die under authoritarian regimes.

Rows of people standing and holding hands (© Robert Tonsing/AP Images)
Residents of Tallinn, Estonia, join hands on August 23, 1989, in a human chain stretching from Tallinn to the Lithuanian capital of Vilnius in a symbol of solidarity known as the Baltic Way. The woman`s pin in the foreground reads “MRP 50,” referring to the 50th anniversary of the Molotov-Ribbentrop Pact. (© Robert Tonsing/AP Images)