Was appeasement a mistake?
Yes, it was a mistake
It gave Hitler more resources and land – this allowed him to build up his armaments even more and gain more soldiers for his army, as well as achieve his aim of lebensraum
It encouraged Hitler – every conquered territory made Hitler seem stronger in Germany and gave him the opportunity to go further. E.g. Sudetenland and Czechoslovakia etc. He would have backed down at the sight of one French soldier in the Rhineland. It was clear from his aims that Hitler wanted a war
Gave Hitler time to rearm — every country he conquered gave him more troops. It convinced the German people that Hitler’s ideas of Arian superiority were true, and fed into his propaganda narrative!
It scared Russia – they ended up signing the Nazi Soviet Pact and felt excluded from the West. Russia weren’t invited to Munich Conference either, which made them more anxious, and more likely to do a deal with the devil
'"My good friends, for the second time in our history, a British Prime Minister has returned from Germany bringing peace with honour. I believe it is peace for our time." Chamberlain (Source: Ministry of Information official photographer)
No, it was not a mistake
It bought time to rearm (the Historian AJP Taylor though believed that German troops were only 45% of what British intelligence reports said they were) Britain increased its aircraft from 1800 to 8000 from 1936-1939
The British public were not ready for war – after the horrors of WW1 the public needed to be totally convinced to fight a war. Hitler’s actions showed the public that he was a megalomaniac and that war was necessary.
The Treaty of Versailles did seem too harsh – Chamberlain therefore thought it was only reasonable that Hitler reconquer some of his own land (e.g. Rhineland that had been demilitarized in TOV). They were ‘only marching into their own backyard’
Hitler was a valuable ally against Communism – The USSR seemed a much stronger, and potentially more dangerous enemy than Hitler. Hopefully it was thought that the two would fight each other. Communists were feared as one of their goals was a World Revolution. The West was afraid enough of Communism to back The Whites against the Communists in Russia, 1917.
Hitler and Chamberlain at Bad Godesberg, Munich, Sept 1938 (Source: Bundesarchiv, Bild 146-1976-063-32 / CC-BY-SA 3.0)