It looks increasingly improbable that Egyptian leader Mohamed Morsi can navigate his way out of the crisis engulfing his presidency.

While a deadline from opposition campaigners for their demands to be addressed expired yesterday, most eyes were still on the army's separate ultimatum which runs out this afternoon.

Opposition demands were bolstered by the millions of Egyptians who turned out to demonstrate against Mr Morsi on Sunday. Their one key call is for Mr Morsi to stand down and offer fresh presidential elections.

Rival pro-Morsi protests held in Cairo's Tahrir Square yesterday were modest by comparison but Mr Morsi's defenders are surely right to point to his democratic mandate. They object that if he is forced out there is nothing to stop subsequent democratically elected candidates facing the same fate whenever they become unpopular. That is true, but when protests bring such vast numbers on to the streets, it is hard to equate that with the mid-term blues routinely seen in other democracies.

While a campaign of civil disobedience is now promised by opposition groups, the plans of armed forces chief General Abdel-Fattah el-Sisi are far from clear.

He called on Mr Morsi and the opposition to end the public unrest within 48 hours, pledging that the army would otherwise intervene and set out its own road map for change. This seems to include rule by an interim council ahead of a new constitution and presidential elections.

International anxiety over the situation has been growing and US President Barack Obama has called for Mr Morsi to acknowledge that democracy is about more than simply election results. The regime run by Mr Morsi and the Muslim Brotherhood has been autocratic, opponents argue, and Egypt's current leadership has failed to recognise that democracy must go further than the ballot box. Other White House sources have appeared to suggest that Mr Morsi should tackle unrest by appointing a new prime minister and reshuffling his cabinet.

It is hard to know what to propose to prevent a gradual slide towards civil war in a region which is already highly unstable due to the crisis in Syria and large anti-government protests in Turkey.

While protesters hope fresh elections might see a new, more revolutionary leader elected, there are few obvious candidates, and the prospects for a peaceful resolution if the army steps in, perhaps putting Mr Morsi under house arrest and imposing new elections, are not good.

Facing ministerial resignations and little prospect of forming a working government, Mr Morsi's defiant insistence on seeing out his term is surely equally implausible.

In a country which was so key to the so-called Arab Spring, preserving democratic principles is vital. It may not be ideal, but the best chance of doing this is for Egypt's leader to forestall army intervention by calling new presidential elections, with the hope that this can renew rather than confound the achievements of the 2011 revolution which toppled Hosni Mubarak.