HARRISBURG — The League of Women Voters is leading a new lawsuit seeking to throw out the map of Pennsylvania’s congressional districts as an unconstitutional gerrymander that favors Republicans and violates the rights of Democratic voters.

The lawsuit was filed Thursday in the state Commonwealth Court. It is the first to challenge districts originally drawn by Republican state lawmakers in 2011. It says Pennsylvania’s map is one of the worst gerrymanders in the country.

Republicans fill 13 of Pennsylvania’s 18 seats in the U.S. House, despite winning roughly half of the statewide congressional vote in three ensuing congressional elections.