20/20 hindsight is always more accurate than decisions made under pressure, when the situation is fluid, and with less than perfect information.
If the leaders of the UK had the courage/will to step in when Hitler started down the road that led to WW2, WW2 might not have happened. If PM Stanley Baldwin had stepped in when Germany violated the terms of the Treaty at Versailles by remilitarizing the Rhineland in 1936, it is possible that Hitler would have been inhibited from the annexation of Austria and the occupation of Czechoslovakia, both in 1938. Of course, Baldwin had to deal with the crisis of Edward VIII abdicating and George VI assuming The Throne, so he has to get a little latitude/consideration for being preoccupied.
OTOH, Chamberlain clearly appeased Hilter and Hitler, being a "given an inch, take a mile" sort of person recognized that Chamberlain would do anything to avoid war. In contrast, Hilter saw war as a reasonable means by which to further his goals. The rest, as they say, is history.
