While that's often true in general, Chamberlain was less clearly to blame than he's often made out to be. By the time of the infamous "I have in my hand a piece of paper" thing, it was already too late to stop the Nazis easily (it might have been done earlier, but not then). Chamberlain was told very clearly by his military advisors that the British military could not stop the Nazis by force at that time and he started to increase the rate at which the British military was being increased, especially the RAF (which was rightly thought to be crucial). Chamberlain might have been right. He certainly wasn't as obviously wrong as he's often made out to be.