Virginia Gov. Bob McDonnell has emerged as one of three Republican officeholders who political handicappers say have the most potential to unify the party and boost the fortunes of GOP standard-bearer Mitt Romney as a running mate in November.

Virginia Gov. Bob McDonnell has emerged as one of three Republican officeholders who political handicappers say have the most potential to unify the party and boost the fortunes of GOP standard-bearer Mitt Romney as a running mate in November.