"Like father, like son.

Sen. Bob Casey Jr., a conservative Democrat from delegate-rich Pennsylvania, will endorse Sen. Barack Obama this morning in Pittsburgh, the first prominent Keystone State Democrat to say no to Sen. Hillary Rodham Clinton.

In 1992, Casey's strongly anti-abortion father, then-Gov. Bob Casey Sr., refused to endorse Bill Clinton for the presidency and was barred from speaking at the Democratic convention. His son, a low-key former state auditor, had said he would remain neutral in the race until after the state's April 22 primary.

According to the Philadelphia Inquirer, Casey changed his mind in recent days as he watched Obama grapple with the fallout of the Reverend Wright debacle. He also was swayed by his four daughters, all Obama fans.

Until today, Clinton was the clear establishment choice in Pennsylvania, with a heavyweight lineup that includes Gov. Ed Rendell, Philadelphia Mayor Michael Nutter, and veteran Rep. Jack Murtha. Polls show Clinton favored to win on April 22.

But Obama is making a big push, spending over $1.6 million on ads and embarking on a 6-day bus tour that begins today, with Casey tagging along for part of the trip. The campaign hopes that a stronger-than-expected showing in Pennsylvania could quell concerns among uncommitted superdelegates about Obama's ability to win lower-income white voters, in particular men.

In Pennsylvania, these voters are known as "Casey Democrats." They are economic liberals but social conservatives, Catholics who oppose abortion but support gun rights, and they helped Casey to beat popular GOP Sen. Rick Santorum in 2006." (Shailagh Murray, The Washington Post, March 28, 2008)