Summary: Obama gets boost in race
CANDIDATE SUPPORT: Pennsylvania Sen. Bob Casey Jr. endorsed Barack Obama at a boisterous rally Friday. Hillary Rodham Clinton noted her own support, including Philadelphia Mayor Michael Nutter, anti-war Rep. John Murtha and Gov. Ed Rendell.
ANOTHER BOOST: Vermont Sen. Patrick Leahy said Clinton was never going to win enough delegates and suggested she quit in "the interests of a Democratic victory in November."
THE STATE: Pennsylvania polls show Clinton leading by double-digits. The April 22 vote will allocate 158 delegates, the biggest prize left in the nomination battle. 