ALLISON PARK, Pennsylvania — “I have heard the two most important days in your life are the day you are born and the day you figure out why,” Sean Parnell said Tuesday. The retired Army vet and Allegheny County Republican was alluding there to 9/11, the event that had prompted him to join the military and serve his country. Parnell brought this up as he was announcing his candidacy for the U.S. Senate.

Parnell is seeking the seat currently held by Lehigh Valley Republican Sen. Pat Toomey, who is retiring after his second term.