I recently read something (probably not very accurate though, I expect Dachs to shoot this to pieces) that suggested Bismarck provoked Napoleon III. Napoleon declared war at a moment he wasn't really for it, while the Prussians were ready.
It's significantly more complicated than that.
By 1870, the French Empire - or at least, its government, especially the foreign minister, Lord Gramont, and the premier, Ollivier - was spoiling for a fight against Bismarck's Confederation. The chancellor had been the architect of a French humiliation over Luxembourg in 1867 and, lately, had been looking more and more like the arbiter of Europe, a position Napoleon had held himself for some decades and which he was loathe to relinquish. Bismarck elected to test the waters of the Liberal Empire's new government, so to speak, with a diplomatic gavotte, putting in a Hohenzollern prince, Leopold of Hohenzollern-Sigmaringen (the south German, Catholic, slightly estranged branch of the family) up for consideration as the king of Spain, whose throne had been vacant ever since Isabel II was forced out two years before.
This was not a meaningful geopolitical ploy. Spain was not an autocracy even under Isabel, and under Leopold the Cortes was certain to have a very great deal of authority. It was hardly as though changing the Spanish king from a Bourbon to a Hohenzollern would make the country into a collection of diehard Prussian allies, ready to unleash their armies across the Pyrenees at Bismarck's beck and call. It was 1870, not 1570. Leopold himself didn't care much for Bismarck or Prussia and probably wouldn't have done anything even if he
did have the ability to start a Franco-Spanish war with a single order. So this was hardly a Teutonic master plan to encircle France and certainly not a meaningful threat to French security. It was a matter of prestige, nothing more.
Since King Wilhelm, an actor who is frequently overlooked in comparison to Bismarck and Moltke but who had a very great deal to do with running his country and making the decisions often credited to those two best known of his subjects, was not very interested in the candidacy project, it probably wouldn't have succeeded even if everything had worked out properly, but a bit of bad luck at the telegraph office meant that the French found out about the whole thing before the Cortes could vote on it, preventing Bismarck from having his
fait accompli. (Suggesting that Bismarck planned for the Spanish diplomatic decryption service to misread the telegram so as to create his crisis for a war with France is more than a little ridiculous.) The French were predictably annoyed. "Annoyed" hardly makes for a war, though.
But Ollivier and Gramont soon began spinning the government up for conflict. The foreign minister read out a prepared statement to the
corps législatif declaring "peace if that is possible, war if that is inevitable", a fairly outrageous response to an imbroglio over a Spanish throne whose political and diplomatic importance was virtually nil next to the policies of strongman Juan Prim and the Cortes. Gramont also sent the ambassador to Prussia, Vincent Benedetti, to the Ems spa to confront Wilhelm over the whole thing and make sure that the candidacy was withdrawn (Wilhelm being the head of the Hohenzollern house in addition to king of Prussia). This last was basically the equivalent of barging into the king's occupied bathroom, a
faux pas and expression of insolence and disrespect that itself can be reasonably construed as having been designed and calculated to provoke a war.
Wilhelm, of course, took the eminently sensible path of telling Benedetti that the whole thing wasn't supposed to start a war, that he'd had no idea it would've started such a firestorm in Paris, and that he thought the whole thing was a bad idea anyway, with no hard feelings and all that. Benedetti reported this to Paris while adding the caveat that Wilhelm might just be stalling for time to prepare for war, which Dennis Showalter describes as either boilerplate or a CYA that unfortunately had more of an effect than the rest of the telegram combined. Gramont viewed the whole sequence as prevarication and delaying tactics from Wilhelm and instructed Benedetti to get a hard commitment on a withdrawn candidacy from the king. Wilhelm stalled; he was reasonable about the candidacy, but "reasonable" didn't extend to "making state and family policy because the French government demands it". Nevertheless, within a few days Leopold and his father had withdrawn the candidacy regardless.
Apparently this wasn't enough for Ollivier
et al. One can't quite talk of a conservative camarilla at Paris, but there were pressures on Napoleon III from multiple angles, ranging from a Gramont who wanted to cement his reputation as the French Bismarck to the Empress Eugénie, who wanted a glorious war with Prussia in order to provide an excuse to crush the liberals in the Empire and restore a proper conservative Catholic monarchy for her son Louis instead of the weak reed she considered the Liberal Empire to have become. So Benedetti got new instructions: go back to Ems and force Wilhelm to promise that the candidacy would not be renewed in the future.
It was not as though this step was taken due to considerations of public opinion. The crisis developed too fast for a real sense of that opinion to develop, anyway, and what did exist was generated by the Paris papers, most of which were being led by the nose by the government anyway. The French government was not taking its decisions about pushing Prussia harder and harder in a vacuum, but public opinion was not seriously considered. There was no sense of the government being forced into more and more radical policies by the bloodthirsty Paris mob. In fact, there were more than a few instances of unrest in Paris caused by the
government's overly aggressive policy, not the other way around.
Still, there was at least a reasonable possibility that the new demand would succeed. Benedetti had, after all, barged into the Ems spa and come away from his previous meeting with the Prussian king reasonably well, with little rancor. If that was not indicative of good rapport, little else could be. In addition, Gramont, like most contemporary European diplomats and subsequent historians, thought Wilhelm was a lot dumber than he actually was, and calculated that he could probably be convinced into the policy anyway. The king ended up proving this last wrong; he refused to give Benedetti an audience and told him to discuss the matter through Bismarck (who had been on holiday at his estate for most of the crisis), but acted politely throughout and, at the end of the whole thing, did the whole 'tip of the hat' thing and left when it looked as though Benedetti might cause a public scene. Bismarck's subsequent editing of the telegram, while it did make the whole thing look more confrontational than it actually was, could hardly be described as a plan for war. The French had been impolitic, overbearing, imperious, and offensive throughout the crisis, and if Bismarck wanted to stir up public opinion against them on those grounds he hardly had to edit a telegram to do it.
Ultimately, the Ems telegram was irrelevant to the outbreak of war, or at best only peripherally relevant. Gramont and Ollivier had pushed as far as they deemed possible without a war. Ollivier, at least, started to backpedal somewhat at the eleventh hour; in a heated Council of State meeting, he and Napoleon vacillated (suggesting instead that the crisis be turned into a springboard for a Great Power congress to further bolster French prestige and embarrass Prussia) while Gramont and the war minister, Edmund Leboeuf, took up the roles of hawks. During a recess, though, Eugénie ended up changing Napoleon's mind, and he came down firmly on the side of war. It didn't hurt that Leboeuf practically oozed confidence throughout; it was not hard for Napoleon, annoyed by his wife, pained by his kidney stones, and generally less and less sure of himself as the crisis went on, to pick up on the decisions of a more confident man and roll with them. "At least Leboeuf knows what he is doing", that sort of thing. (The irony, given what actually ended up happening during the war, is palpable.) He ended up approving mobilization orders, and the next day the council put the rubber stamp on a declaration of war.
The French remained in the driver's seat of the crisis throughout; in fact, they're the reason that it can be called a crisis at all. For reasons of diplomatic prestige and point-scoring, Ollivier and Gramont inflated an international
faux pas into a major diplomatic incident and supposed issue of national honor; as soon as scoring points got harder, the government eventually lumbered into war. If anybody had cause for anger or insult at the whole thing, it was Wilhelm, who ended up being the most level-headed out of anybody and persistently did far more than could be reasonably expected of a man in his situation to avoid an incident, much less war. Bismarck, on the other hand, was only barely involved in the majority of the crisis, and did little other than test the French to see about their new government's intentions while doing his best to keep his options open. He certainly did not do much to avoid war, but he cannot be reasonably said to have caused it, either.
And the whole crisis definitely did not impact France's readiness for the fight or its ability to seize the initiative. Apocryphally, Leboeuf is said to have declared that the army was ready down to the last gaiter button; it was quite an exaggeration, but the basic sentiment - that France was much better prepared for a war from a standing start than the Germans were - was sound. France mobilized faster than the North German Confederation and its allies did (and it didn't hurt that, because the French were the aggressive party in the whole crisis, that they had actually issued mobilization orders first by two days). The French had all eight of their corps in position several days before the German armies had deployed in reasonable numbers. (As it was, the German forces that engaged the French at the initial encounter battles at Saarbrücken and Spicheren were still not fully concentrated, and Moltke would continue moving up his first few echelons throughout the August campaign.) If Napoleon, or anybody else, had actually commanded an offensive to seize the initiative and cross the Rhine, the French
militarily could have done it. It was hardly a guarantee of success, especially in the face of Moltke and the new-model North German armies, but it certainly would've improved French chances by a very great deal. The Emperor simply failed to do so, he failed to designate someone to exercise overall command instead of him,
and nobody else wanted to take responsibility for the whole thing. So the days that the French mobilization had bought France were converted into some ridiculously minor "advantages"; one French corps took up an advanced defensive position a few miles inside the Saarland, and another entrenched around the aforementioned Spicheren, also within a few miles of the border.