Uncertainty continues to grip Egypt this morning, with demonstrators massed in Tahrir Square apparently unappeased by the regime’s response to the weekend’s violence.

In a televised address overnight, field marshal Hussein Tantawi — head of the supreme council of the armed forces and the country’s effective ruler — accepted the resignation of the interim civilian government, promised again that the military had no ambitions to rule and would withdraw completely from politics if the people demanded it, and agreed to hold presidential elections by June next year.

That’s real progress, and if he’d said those things last Friday, Tantawi would have been well received. Even now, as the BBC’s Yolande Knell puts it, “While such announcements fell short of what demonstrators have demanded, they might be enough to convince many Egyptians who haven’t joined them on the streets.”

But unless things calm down, it’s going to pose serious difficulties for Egypt’s legislative elections, scheduled to begin next Monday and run in three stages until 10 January. There’s an intense debate under way about whether or not they should be postponed.

Marc Lynch at Foreign Policy argues for postponement, saying “It is unlikely that a body elected under these conditions will command real legitimacy” but stressing that there needs to be “a much more dramatic and immediate transfer of power to a civilian government, with clear commitments to overseeing a rapid move towards elections.”

Shadi Hamid at the Atlantic, on the other hand, says that “delaying elections … would be fraught with dangers that could make the last few days look tame by comparison”, and that “such a situation could spiral wildly, and violently, out of control.”

Any country new to democracy faces the question of how soon to hold elections. Go too early and you risk logistical unpreparedness and disadvantaging new political forces that have not had time to properly organise. Leave it too long and you lose momentum and create a democratic deficit, with the risk that the “interim” rulers will develop a taste for power and be reluctant to give it up.

Tunisia, first cab off the rank in the Arab Spring, seems to have got it about right, holding a very successful election last month that produced a coalition government led by moderate Islamists. Egypt, however, faces more of a challenge.

These elections have already been postponed once; they were originally planned for September, but that proved impossible to organise in time.

Egypt is a big country, so elections will be a major undertaking, but they are not starting completely from scratch — there were elections, albeit unfair ones, under the Mubarak regime, so at least some of the infrastructure should be in place. (The three-stage model is itself carried over from that era.)

When the elections are held, there’s general agreement that the Freedom and Justice Party, the vehicle of the  Muslim Brotherhood, will do well.

It was the Brotherhood that began the current round of protests last week only to lose control of them at the weekend, and the Brotherhood apparently played the main role in talks that led to Tantawi’s statement this morning.

Of course if the generals really want to hold power for themselves at all costs, this would be an ideal opportunity to cancel the elections. But if it were not obvious already, the past few days have made it clear that the people will not stand for that and that indefinite military rule could be sustained only by enormous bloodshed.

If Hosni Mubarak couldn’t get away with it, there’s no reason to think his successors would either. As I said in February, “No one expects a random Egyptian general to be a committed democrat, but one who owes his position to a popular uprising will be in a very different position to a long-standing incumbent dictator.” If Tantawi’s concessions haven’t done enough to calm the protests, most likely he’ll continue walking backwards until they do.

Most of all, what the generals want to avoid is civil war. That’s why the thought of cancelling the elections immediately brings to mind the example of Algeria, where military intervention in 1991 prevented an Islamist victory but set off a civil war that killed some 150,000 people.

Fear of that outcome was one thing driving the curious relationship Mubarak had with the Brotherhood, now continued after a fashion by Tantawi. Although officially outlawed, the Brotherhood was tolerated as a semi-official opposition, a sort of safety valve for the regime. It performed the dual function of preventing dissent getting out of control while sidelining the more liberal forces that might have attracted Western support.

It seems that the Brotherhood still has a foot in each camp, and that holds out some hope of reaching common ground between the military rulers and the masses in Tahrir Square.