The counter-revolutionaries are using bigger bombs against the coaliton forces.
I believe this proves that the neo-baathist/jihadoterrorists realize that their days are numbered; they realize they must stop the election or they lose; they have a limited amount of explosives, but now realize there's no point in rationing the supply for a long drawn out counter-attack over the next year. In other words: it's now or never.
Therefore, I expect the tempo of attacks to increase, too. And therefore, our casualties. DO NOT WORRY. It always gets darkest before the dawn. And remember: In WW2, we took our worst casualties between D-Day and VE-Day. Most were after the Battle of the Bulge.
The tide will turn in Iraq - and in the GWOT - after the huge turnout on Iraqi election day. This will do more to defeat Jihadofascism than sending more US troops.