What would be a good thesis statement for what influenced hitler to invade poland?

Hitler had not wanted war with Poland. He had wanted an alliance with Poland in his anti-Comintern pact against Joseph Stalin.

But the Poles refused to negotiate. Why? Because they were a proud, defiant, heroic people and because Neville Chamberlain had insanely given an unsolicited war guarantee to Poland. If Hitler invaded, Chamberlain told the Poles, Britain would declare war on Germany.

From March to August 1939, Hitler tried to negotiate Danzig. But the Poles, confident in their British war guarantee, refused. So, Hitler cut his deal with Stalin, and the two invaded and divided Poland.

The cost of the war that came of a refusal to negotiate Danzig was millions of Polish dead, the Katyn massacre, Treblinka, Sobibor, Auschwitz, the annihilation of the Home Army in the Warsaw uprising of 1944, and 50 years of Nazi and Stalinist occupation, barbarism and terror.