CAIRO — Courts and factions engaged in a frantic last-minute scramble on Wednesday in a struggle for power over the culmination of Egypt’s ­political transition after the ouster of Hosni Mubarak. The two highest appellate courts went on strike, the Supreme Constitutional Court accused the president of blackmail, the Islamist leaders of the constitutional assembly rushed to complete the charter by the end of Thursday, and the Muslim Brotherhood called for a major demonstration on Saturday.

The dueling marked an escalation in a two-front war pitting Egypt’s Islamist president, Mohammed Morsi, against the country’s courts on one side against a galvanized opposition in the streets and on the other that drew hundreds of thousands of Egyptians to Tahrir Square a day earlier in the biggest demonstration against Morsi since his election in June.