From this morning Beltone Financial newsletter, by an Egypt-based regional investment bank that does a pretty good roundup of local news:
The size of masses to protest against Morsi, the duration and intensity of the protests, the role of the army, and the support of the west including the US will all determine the outcome of the protests. We are inclined to believe that the end of Morsi’s presidency is looming, but that it will likely take deadly clashes and continued civil disobedience. This may extend beyond the week of June 30th, thus extending the length of political instability in Egypt. We also believe that it would take army intervention to control the Muslim Brotherhood before and after Morsi steps down. The Brotherhood’s dream of a caliphate in the region and beyond is at stake and they will not give up that easily. The West will stop supporting President Morsi only when they see the Egyptians themselves all turn against him. The lack of US and western support of President Morsi will definitely turn the table against him and will result in the end of his rule. The army will intervene when the clashes become deadly and widespread, yet it is unclear whether their role will end there or if they will aspire for more power and thus the scenario whereby the Egyptians turn against the army starts again.
Yup - but it's a tall order to align those conditions. So far, the army is waiting and Obama is supportive of Morsi as legitimately elected leader. But that could change fast.