I have a burning question about the anti-nazi alliance proposed by the Soviets following Anschluss when in the 12th of March 1938 when Hitler invaded Austria, the Soviet People’s Commissar of Foreign Affairs before Vyacheslav Molotov, Maxim Litvinov proposed a collective security defence pact with France and the UK. It was on the 17th that Soviets send out a diplomatic letter to state its readiness to enter with discussion with the League of Nations to halt further Nazi aggression and expansionism. The British Government’s response stated that a conference to take concerted action against aggression would not have beneficially affected the future of Europe. Why were the British so reluctant to even consider the offer of the Soviets?
First off, there were plenty of people in the UK and France who saw the Soviet Union as dangerous a threat as Nazi Germany. The Soviets had been explicitly trying to subvert every country they could since the Comintern had been founded in 1919.
Second, nobody trusted Stalin, with reason. Russia was still in the Spanish Civil War business, in what pretty much everybody (including Stalin) saw as a way to put a communist state on either end of Europe. Every country in Europe had a very noisy and occasionally violent Communist Party, which were all controlled by Moscow. The only country that didn’t was Germany, and that only by outlawing the party.
The Brits (and pretty much everybody else) saw the USSR’s talk of an anti-German alliance as trying to draw them into a war with Germany, the ultimate beneficiary of which would be the USSR. So the British, who saw themselves as being drawn into a war against “aggression and expansionism” was a terrible idea, especially at the behest of a country that would shortly invade Latvia, Lithuania, Estonia, Manchuria and Finland.
Also, the French and British talked themselves into believing that Germany ‘deserved’ Austria, as a Germanic nation. For them, it wasn’t a Casus Belli.