In February, the Pennsylvania Supreme Court imposed a new congressional map after striking down the 2011 GOP-drawn map as an unconstitutional gerrymander. The ruling probably wouldn't have been issued had Democrats not won a majority on the state supreme court in 2015. Nonetheless, the new map gives Democrats the opportunity to four to six more seats than they won in 2016, a net difference of perhaps two seats compared to the current map.

The from-scratch lines will hurt some incumbents, help others and compound the turnover created by five retirements. Overall, there will be six districts with no incumbents running in the fall and one district where two incumbents will face off. Democrat Conor Lamb's victory in the recent 18th CD special election may make him the slight frontrunner over GOP Rep. Keith Rothfus in the new 17th CD, which unites the Pittsburgh suburbs.

This is the ninth in a series of race rundowns designed to give subscribers a quick snapshot of what's happening in each district in 2018. Throughout the cycle, watch for our detailed analysis of the

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