Fifty years ago, we lost a war, and in so doing we lost Sinai, Jerusalem, the West Bank and the Golan Heights. The humiliation seemed complete. Egypt's younger generations are probably immune to the 1967 syndrome, but my generation and those older than it suffered from huge trauma as a result. The defeat shattered our self-confidence and structured our perceptions. During the 1970s and 1980s, perhaps half of my discussions with non-academic friends brought up the war and the period of former president Gamal Abdel-Nasser. The magnitude of the defeat and its historical importance led people in Egypt and across the Arab world to ask why it had happened. Had it been unavoidable? What kind of lessons should we draw from this episode? There were various opinions. Some considered the Nasserist-Arab nationalist project to be a stupid one implemented by stupid politicians. Others opted for a different stance: The Nasserist-Arab nationalist enterprise was acceptable, they said, but it had suffered from the stupidity of either Nasser or Abdel-Hakim Amer, at the time the number two figure in the Egyptian regime and the head of the military, or both. My view was different: All the available data and all his deeds showed Nasser to be an outstanding statesman, a leader of exceptional stature, and a politician with considerable skills. The problem lay elsewhere: In the project and its dynamics, in the regime's structure or nature, or maybe in a mixture of both. The Nasserists faced a dilemma, and they were adamant, at least in public, that Nasser had not made mistakes. But they could not accept the logical consequences of this view. If this kind of defeat had been unavoidable, then the Nasserist project was too dangerous for his advocates and for the Arab countries as a whole. The Nasserists refused to accept this conclusion, of course, and they preferred to say the fault was Amer's, or they simply fell back on various conspiracy theories. They were not the only ones to do so. There are at least three different narratives that rely on such conspiracy theories. The first was popular within the ruling elite and with public opinion. Nasser was the victim of an American conspiracy, it said. The American establishment could not tolerate a third world leader of such stature. It could not accept the fact that he had radically challenged the West's hegemony in 1956 and had got away with it. This was an awful precedent, and he had to be made to pay for it, lest others try the same thing. So the Americans decided to target Nasser, and after many years he finally fell into a trap. The most elaborate version of this narrative is by the late Egyptian journalist Mohamed Hasanein Heikal in his famous trilogy of books. These were best-sellers, but two American academics, William Quandt and Richard Bordeaux Parker, tested the argument thoroughly and came to the conclusion that there had been no trap and there had been no American plot. Washington had been taken by surprise by the crisis, they said. True, by the end of May 1967 then US president Lyndon Johnson had decided to side with Israel and was calmly fooling Nasser. But the crisis was not a well-thought-through American plan. I was told by an Egyptian historian that Heikal in his final years had radically reconsidered his narrative and had implicitly admitted in articles published in the monthly Cairo magazine Wijhat Nazar that it was unsatisfactory. Today, the academic consensus says that Washington was angry with Nasser at the time, and that he had become an enemy to London, Riyadh and Tel Aviv. Many members of the foreign policy community advocated taking a tough stance against him. But there was no plot and no policy to get rid of him, as he was the most realistic of all radicals. Another narrative says that the defeat was caused by a Soviet plot. This may seem strange as Moscow was Nasser's main ally at the time. The proponents of this narrative propose two explanations: They say that Moscow wanted to get rid of Amer, who was a staunch anti-communist, and that it expected a small defeat in 1967 that would be enough to achieve this aim. However, instead what they got was a complete collapse. The other explanation is that they were fed up with Nasser's independence and unpredictability and wanted to downsize him and to turn him into a more malleable Soviet client. This sounds, and indeed is, fanciful. However, it rests on two facts. First of all, there was the groundless Soviet warning claiming that the Israelis were mobilising troops to attack Syria. This led Nasser to escalate his preparations against Israel. All former Soviet officials swear this warning was a mistake, and it probably was, but I still do not know how such a mistake could have happened. Secondly, there was Moscow's failure to provide Egypt with a credible air-defence system. However, this failure is more easily explained as Nasser had been fighting previously in Yemen, where he faced no air threats. He was not expected to open a new front against Israel when at least a third of his troops were defending Yemen's republican regime. Moscow also had another client that did face an intense bombing campaign in North Vietnam, and this Communist country that was facing the US air force took priority. Some say defending the Syrian regime, far more left-wing than Nasser's, was Moscow's main intention, and protecting it could even have meant sacrificing Nasser. However, it seems that this analysis is wrong as Moscow relied on Cairo and not on Damascus. The third type of conspiracy theory is even more absurd since it says that Nasser was his own victim. He wanted to get rid either of Amer or of some of his aides, and a crisis was a welcome way to do so. Either he would win the diplomatic game and gain enough prestige to fire Amer, or he would lose control of Sharm El-Sheikh and Amer would be the scapegoat. He never considered the loss of Sinai as possible, this story goes. It does not deserve discussion, as it is absurd and nothing substantiates it. These theories do not say the defeat was unavoidable, despite the league of evil fighting against us. Nasser was also the victim of Amer's supposed incompetence and his refusal to share information with his boss. Amer, sensing Nasser's hostility towards his lieutenants, would not let the president interfere in the army's affairs. This view deserves serious discussion. Suffice it to say here that it is not groundless – it is even plausible – but it overlooks the fact that Amer's job was to guarantee the army's allegiance to the regime. Moreover, he had not been responsible for the budget cuts that had harmed it. The writer is a professor of international relations at the Collège de France and a visiting professor at Cairo University.