Biden, Sanders Highlight Familiar Split In Democratic Party

Bernie Sanders and Joe Biden are very much on each other's minds.

At his campaign rally in Philadelphia Saturday, Biden went off script — twice — to deride a protester with a whistle.

"That must be Bernie or somebody," Biden said, raising eyebrows and drawing laughs.

Minutes later, with Biden talking about unity and governing amid more background whistling, he used the whistler as a punch line.

"You know, there's serious work that has to be done," Biden said, "but it's not being done by a president who wakes up...