PA's Casey Endorses Obama

In a surprise move PA Senator Bob Casey endorsed Obama with just over three weeks to go until the PA primary.

It is the battle of the PA heavyweights:

Casey, the son of a popular late governor, had said earlier this month he would not endorse before the April 22 primary out of concern for party unity. But he joined Obama at a boisterous rally kicking off a six-day bus trip through Pennsylvania, where current Gov. Ed Rendell has been campaigning hard for Clinton.

Which machine will win.

At this stage, Obama doesn't need a win, just a narrow loss to keep the delegate lead.