Which is largely how World War II started in Europe: Stalin and Hitler agreed on a partition of the lands in between, and together started a war to implement that agreement, so that their armies could shake hands in the middle of Poland.
https://en.wikipedia.org/wiki/Munich_Agreement
"The agreement was signed in the early hours of 30 September 1938 (but dated 29 September) after being negotiated at a conference held in Munich, Germany, among the major powers of Europe, excluding the Soviet Union."
The German-Soviet Molotov-Ribbentrop pact was signed in August 1939, almost a year later.
Sure, Chamberlain was wrong with that peace in our time and handing Bohemia to Hitler. But obviously he had difficulty in going to war over it, as well.
And Arthur Harris would have hung as a war criminal if Britain had been on the losing side against Germany. But that's a different story. The two dictators and systems in their countries were the ones most responsible for bloodshed.
So is that a fear in Poland? That peace with russia would involve handing over parts of your country to Russia?