Hopes for a swift end to Egypt's impasse faded on Monday as opposition leaders rebuffed a call by President Mohamed Morsi for a "national dialogue" amid violence that cast a long shadow over the second anniversary of the revolution that overthrew Hosni Mubarak. Fifty dead, hundreds of arrests, curfews and a state of emergency in three provinces were stark reminders of the volatile standoff between Morsi's Islamist and conservative supporters and secularists, liberals, left-wingers and Copts.