Egypt’s Islamists and secular activists prepared for their last rallies before a constitutional referendum that may decide what kind of state emerges to replace Hosni Mubarak’s autocracy.

Supporters of President Mohamed Mursi from the Muslim Brotherhood, which is leading the “yes” campaign, have called for a million-man rally starting from the Rabia al-Adawaiya mosque in eastern Cairo, according to the group’s website. The Brotherhood says approval of the constitution will stabilize the country and pave the way for economic recovery.