The generals in charge of Egypt have given parliament two days to form a committee that is tasked with rewriting the Arab country’s constitution. Field Marshal Mohamed Hussein Tantawi warned that the army would name a panel if the legislature fails to do so.

Lawmakers of the Muslim Brotherhood’s political wing have vowed that they will not accept the military ultimatum nor a panel that is appointed by the generals.

An earlier attempt to form a constitutional panel failed because the Brotherhood, which is by far the largest faction in parliament, tried to stack it with its own members. Christians, women and other minorities were highly underrepresented. This sparked fears among moderate Muslim and liberal Egyptians of an Islamist takeover.

Those fears were aggravated when the Muslim Brotherhood’s candidate was among the two who made it into the second round of Egypt’s presidential election which is scheduled to take place later this month.

After last year’s first free parliamentary elections since the fall of Egyptian strongman Hosni Mubarak in early 2011, a power-sharing agreement seemed to loom between the Brotherhood and the military. The army reached out to the Islamist group and appeared willing to hand it control of domestic affairs as long as the generals could maintain their influence in defense and foreign policy.

If there was such an understanding, it was shattered when the Brotherhood broke its pledge not to contest the presidential election.

With an Islamist majority in parliament and the possibility of a Muslim Brotherhood president taking over from the army’s interim government in July, the group dominating the constitutional panel became untenable.

The army would like to have a new constitution in place before it hands power to the elected president next month. In it, the military’s control of national-security policy and vested economic interests should be enshrined.

The Brotherhood would rather wait until after the election, which it hopes to win, so it can eradicate the vestiges of the old regime which persecuted it as a sect for decades of military rule. The Muslim Brotherhood was outlawed as a political organization during Mubarak’s reign while any trace of Islamic fundamentalism was suppressed under anti-terrorism laws.