Historical revisionism is always in season and is generally a useful, or at least diverting, activity. But Nick Baumann’s effort, in Slate last week, to resuscitate the strategic reputation of Neville Chamberlain (British prime minister, 1937–40), on the 75th anniversary of the Munich Agreement, was a bridge too far in historical myth-making.

It is correct that Britain and France could not go to war to prevent Germans in Czechoslovakia, especially concentrated in Sudetenland, from becoming Germans in fact; and that, as a practical matter, this meant conceding Sudetenland to Germany, as the Czechs could not deport a million Germans without justifying and bringing down on themselves an irresistible German invasion.

Baumann breathlessly revealed what every even slightly informed person on the subject already knew: that Britain and France had no ability to stop Germany on the ground in Central Europe. Even at the end of World War II, Britain had only 25 divisions engaged against Germany in Northwest Europe and Italy (compared with 80 U.S. and 16 French and Canadian combined). The British army (like all other armies) could defeat the formidable Germans only when they had they had a heavy numerical and armament advantage, as at El Alamein in Egypt in November 1942. No sane person ever suggested that Czechoslovakia could be successfully defended from Hitler militarily if he attacked it....