What political people are saying about Tuesday's Democratic primary in Pennsylvania:
"Hillary Clinton had a good night but not a great night. Tonight keeps her racing around the track. But after 150 laps in the Indianapolis 500, she won't pass [Barack] Obama unless he runs out of gas."
PETER FENN, Democratic strategist
"The notion that Obama cannot attract core constituencies is only being tested in matches against Hillary Clinton. That's not an argument that he can't win them against John McCain."
PHIL TROUNSTINE, director of the Survey and Policy Research Institute at San Jose State University
"She can't win but won't quit."
JIM JORDAN, Democratic strategist
"The increasingly negative tone in the primary could hurt our prospects in November. ... I do think we're playing with fire."
CHRIS VAN HOLLEN of Maryland, chairman of the Democratic Congressional Committee
"If Senator Clinton thinks she has a legitimate chance to win the nomination, she has every reason to stay. But if her only strategy is to try and tear down Senator Obama, I think that's going to make a lot of Democrats uncomfortable."
DAVID AXELROD, chief strategist for Mr. Obama