Your report (30 July) says the deciphering of the Zimmermann telegram (inviting Mexico to ally itself with Germany) by British intelligence “changed the course of the first world war, bringing the US into the conflict”. US belligerence was pretty much certain once the Germans began unrestricted submarine warfare in February 1917; Zimmermann’s daft ploy – symptomatic of the dysfunctionality of the imperial German government – was a desperate, but futile, attempt to offset that almost inevitable outcome was bound to fail: neither Mexico nor Japan were going to take the bait. When adroitly used by British intelligence, it may have marginally accelerated US belligerence – not by unifying American public opinion (it did not) but by stiffening President Woodrow Wilson’s resolve. Absent the telegram and the plot, that marginal delay would not have affected the outcome of the war.
Alan Knight
Professor emeritus of the history of Latin America, St Antony’s College, Oxford
