For third time this year, a special election will decide control of the Pennsylvania House. In July, the District 21 seat in Allegheny County became vacant when that legislator resigned to focus on her campaign to become county executive. Her resignation eliminated Democrats’ slim majority in the House and left them tied with Republicans for control. Now, Allegheny County voters will go to the polls in a special election next month to choose between Democrat Lindsey Powell and Republican Connolly Autenrieth. The outcome will determine which party will retain a majority. The special election will be held September 19th, before the legislature returns to session.