The impasse into which Egypt has been forced by the army's intervention in politics is daily becoming more dangerous. Every time the security forces open fire, their mission of bringing back order and restoring social peace becomes less credible. You cannot advance toward legitimacy over the bodies of martyrs. Even if it turns out that the casualties in this weekend's violence have been exaggerated or that most were not caused by aimed fire, it is as martyrs that the victims will be, and already are being, seen. A familiar and deadly process, in which protests produce martyrs, and martyrs then produce protests and so on in endless escalation, lies ahead.

Unless it can be stopped – and stopped it must be. John Kerry, the American secretary of state, was stating no more than the obvious when he called on Saturday for dialogue, but his public formulation, at least, avoided the hard fact that the army must back down if a meaningful dialogue is to begin. The Muslim Brotherhood will also have to rethink its position if there is to be any chance of a return to normality in Egypt, but it is the army that must take the first steps. Since General Abdel Fattah al-Sisi staged the coup that removed President Mohamed Morsi from power, it has become apparent that, without quite saying so, he seems to want to cast the Brotherhood in the role of the enemy, or at least to represent it as a political force to be for some indefinite time excluded.

The speech in which Sisi asked the Egyptian people to turn out last Friday in their thousands to give him a mandate against violence and terrorism can certainly be read as an attempt to attach those labels to the Brotherhood. If he did not intend that impression, he certainly did not make it clear that he was not accusing the movement of those sins. Nor has he followed up on his assertion that weapons and military uniforms had been smuggled into the country. By whom? When? And for what reason?

What must deepen these concerns is the attempt to criminalise Morsi. The charges against him arise from the assistance Hamas may have provided in organising jail breaks that freed Brotherhood prisoners, including Morsi himself, in the last months of Mubarak's rule. This may well have happened, and a perverse interpretation of Egyptian law could thus put Morsi in court for murder and espionage. How resistance to a dictator and the security forces he was deploying against protesters, with some help from abroad, could be so interpreted is difficult to see. A wiser hand than Sisi's would have stayed this process. Other "charges", such as "economic sabotage" and the like, are ridiculous. Political mistakes are not crimes in a civilised country. Indeed, if there has been sabotage of that kind, there is some evidence that anti-Morsi forces were the guilty parties.

The general's ambitions for himself represent a further problem. He has begun to adopt a special tone of intimacy, that of the leader in deep discussion with his people, which suggest he sees himself in the line of descent from Nasser. He told Morsi that "his project was not working" six months ago, he said in his speech. Where, precisely, in this soldier's job description is it written that he can tell an elected president what to do? Advise, yes; suggest, maybe; but "tell"?

The Egyptian army's overweening sense of entitlement is an aspect of the country's political pathology. An army that has seen no combat for a generation and faces no serious challenge from external enemies nevertheless absorbs massive resources, enjoys marked privileges, and arrogates to itself special political rights. Egypt should be reducing the influence of its military, not reinforcing it. But, in the immediate future, the decisions of the army, and what are probably now its rather nervous civilian allies, are critical. They must release Brotherhood leaders, find a formula for the rehabilitation of Morsi and a framework for talks that the Brotherhood can accept. Otherwise there will soon be more blood on Cairo's pavements.