Eight-term incumbent Republican U.S. Representative Tim Murphy was involved in a
sex scandal consisting of his allegedly having extramarital sexual relations with a woman and then asking her to have an
abortion. This was particularly damaging because Murphy identifies as a
pro-life politician. Murphy subsequently announced that he was resigning and that he would leave office on October 21. Primary elections were not held in the race. Instead, nominees were chosen by each party. The Republican Party held a special convention on November 11, 2017, to choose a nominee through a conferee process involving 215 local Republican activists. The Democratic Party held their nominating convention on November 19, 2017, in the gym at Washington High School in
Washington, Pennsylvania. The Libertarian Party of Allegheny County and the Libertarian Party of Washington County nominated a candidate via party caucus. At the time,
Pennsylvania's 18th Congressional District was located in
Western Pennsylvania and bordered the state of
West Virginia. It included portions of
Greene,
Washington,
Allegheny and
Westmoreland counties. The district had a
Cook PVI score of R+11. This was the last election for Pennsylvania's 18th congressional district held under the configuration made in 2011 by the
Pennsylvania Legislature as new districts have been drawn in accordance with the ruling of the
state supreme court in
League of Women Voters v. Commonwealth of Pennsylvania and came into effect for the main
2018 congressional elections in November. The bulk of the old 18th became the
14th District. ==Republican conferee meeting==