Wrath of the math: Why did Karl Rove quit?

That's the question on everyone's lips since the porcine political player announced he would be stepping down at the end of August. Of course, the excuse that he wants to spend more time with his family is horse puckey and we all know it--so what's really going on? Is he trying to give Bush political cover if he gets ensnared in one of the many investigations that keep leading back to...