On 13 July 1870, at the spa town of Bad Ems, the French ambassador Count Benedetti approached King Wilhelm I of Prussia during his morning walk. France wanted an assurance that the Hohenzollern candidacy for the Spanish throne — already withdrawn — would never be renewed.
Wilhelm declined politely, said he had nothing further to add, and later sent word through an adjutant that he had no more to say to the ambassador. It was a diplomatic refusal conducted with complete courtesy on both sides. The crisis appeared to be dissolving.
A telegram describing the exchange was sent to Bismarck in Berlin, who was at dinner with Moltke and Roon and in a bad mood, because the peaceful resolution of the crisis had removed his pretext for the war he wanted.
He read the telegram, asked Moltke whether the army was ready, and then edited it.
He changed no facts. He deleted the courtesies, compressed the sequence, and removed the explanatory clauses. What remained read as though the French ambassador had made a demand and the King of Prussia had refused to see him again and had sent an adjutant to tell him so.
He released it to the press and to Prussian embassies that evening.
Bismarck later described the effect in his memoirs with unusual candor: the original would have had the effect of a chamade — a parley signal — while the edited version would have the effect of a red rag upon the Gallic bull. He told his dinner companions that it would produce the impression of a red flag on the Gallic bull, and that France would be forced to declare war, which put Prussia in the position of the attacked party.
France declared war on 19 July.
The mechanism is honor, and it is more powerful in political communication than material interest. Nisbett and Cohen's work on cultures of honor established that perceived public disrespect produces escalation out of proportion to any tangible loss, because what is threatened is standing rather than property. Both publics — French and German — read the dispatch as a public insult, and once an insult frame is established, backing down carries a cost that no rational assessment of the war's likely course can offset.
Two features made the edit effective beyond its content. It was truthful, so no correction was possible. And it arrived through the press as reporting rather than through diplomatic channels as a statement, which supplied credibility that neither government had to claim and neither could be held to.
Aftermath & Cross-Reference: Selective Editing and Media Laundering