The debate was taped Friday at the studios of WPVI-TV in Philadelphia and is slated to air locally on Sunday.
Taking part in the hourlong discussion were Montgomery County Commissioner Joe Hoeffel, Allegheny County Executive Dan Onorato, state Auditor General Jack Wagner and state Sen. Anthony Hardy Williams.
The candidates broke little new ground.
Most of the candidates were stumped when the moderator asked each of them which opponent they would endorse if they were forced to leave the race before the May 18 primary. Only Hoeffel had an answer - he said he'd back Wagner.
Watch the full debate on 6abc and 6abc.com on Sunday at 11:30 a.m.