Casey on Obama: “This is a Campaign for America”

Pennsylvania's Democratic Senator and superdelegate announces his endorsement of the Illinois Senator at a Pittsburgh rally. Watch video above. Casey has big following among -- and symbolic resonance with -- the state's working-class voters. Will join part of Obama's six-day Pennsylvania bus tour. Had originally said he would remain neutral until after his state's April 22 primary. Obama campaign's Friday surrogate talking points: "Working families in Pennsylvania have few stronger advocates than Senator Casey." To read the talking points (which also hit McCain and talk about Obama's economic agenda), click here.