Is this a political miscalculation by the Muslim Brotherhood?

Field Marshal Mohamed Hussein Tantawi, head of the military council that has run Egypt since Hosni Mubarak fell on February 11, promised Tuesday that a civilian president would be elected in June, about six months sooner than the army had planned.

"Leave, leave!" responded crowds in Cairo's Tahrir Square. "The people want to topple the marshal."

The military had originally pledged to return to barracks within six months of Mubarak's removal. Its apparent reluctance to relinquish its power and privilege has fueled frustration among Egyptians who feared their revolution had changed nothing.

Tantawi, who was Mubarak's defense minister for two decades, adjusted the schedule after generals met politicians, including leaders of the once-banned Muslim Brotherhood, which is eager to turn decades of grassroots endeavor into electoral success.

A parliamentary election, billed as Egypt's first free vote in decades, will start Monday as planned, Tantawi confirmed.

To align themselves so closely to the hated military government is a puzzling move for the usually sure-footed Brotherhood. Those demonstrating in Tahrir Square are rank and file Brotherhood members, along with secular youth and leftists. The rejection of the military's plan by the protestors could be foreseen. Perhaps they were so anxious to get the parliamentary voting underway that they sacrificed their perceived independence from the military.

If so, it might affect how ordinary Egyptians view them. While there may be many voters who will see the deal offered by the military as a good one, many more will almost certainly side with the demonstrators. It should be interesting to see how the fallout from the deal affects the final outcome of the vote.