CANONSBURG, Pa. — Pencil in Democrat Conor Lamb or Republican Rick Saccone (suh-KOHN’) as the next congressman in a U.S. House district in southwestern Pennsylvania. But erase their congressional district.

Even after a winner is determined in the too-close-to-call vote from Tuesday’s special election, the prize may prove fleeting.

That’s because Lamb and Saccone soon will have to run in new districts drawn by Pennsylvania’s Supreme Court, the result of a gerrymandering lawsuit filed last year.

Unless a federal court intervenes soon, that new electoral map with 18 districts based on new boundaries will await voters and candidates on the May 15 primary and the Nov. 6 general election.