Just how foul can the left get?

I really do not know the answer to the question in the title - when you think that they cannot get any more unreasonable or hate-filled - along comes something to surprise you.
Let us consider the tragic shootings in Tucson committed (apparently) by a somebody with well known mental problems.
A great many Democrat writers have now blamed the Republicans and The Tea Party and Sarah Palin. (!!!???)
Let us just stop for one cotton-picking moment, here.
By what twisted logical process can any rational person possibly draw such a conclusion? - Quite!