Question

Why didn't France and the UK declare war on the Soviet Union when they invaded Poland?

Answer 1

"The reason why Britain didn’t declare war on the Soviet Union is an intriguing one. Unknown to the general public there was a ‘secret protocol’ to the 1939 Anglo-Polish treaty that specifically limited the British obligation to protect Poland to ‘aggression’ from Germany" http://www.historyextra.com/qa/why-did-britain-and-france-not-declare-war-soviet-union-when-red-army...