The opposition still believes in the possibility to halt the referendum. I hope for them that they succeed, also because the army and maybe the intelligence services are not yet completely controlled by the Muslim Brotherhood (MB) and Morsi.
But if the army, the police forces… not succeed to calm down the unrest, than there is a chance that some new generals, who are MB-appointees, try to commit a coup in favor of Morsi and his party.
You can always hope that they not succeed and that the army remains independent.
But, I don't believe in it.