As usual for events that are meant to be a Turning Point in Iraq, temporary calm has been enforced by a total curfew and vehicle ban during Saddam's judgment. It works, of course, for a few days - but it can't last, as people have to buy food and go to work. Consider it a radical drug from a kit of extreme measures, only for use in a desperate crisis and to be dropped as soon as possible.
Reuters AlertNet reports that the curfew expires at 0600 local time tomorrow. That's 0300Z, 2300 US Eastern Standard Time - or in other words, in time for the first US news cycle on polling day. Haifa Street, a NOIA stronghold area, is around 400 yards from the Green Zone. Snipers have been active in the area for weeks to intimidate US and Iraqi patrols. They could also serve as a stopgroup to hold up relief from outside.
I doubt the NOIA will let their king hang without trying a spectacular.