Voters passed the last November as a Democratic countermeasure to Republican-led redistricting efforts in Texas, Florida and other states. California’s controversial Proposition 50 – passed by voters last November as a Democratic countermeasure to Republican-led redistricting efforts in Texas, Florida and other states – is now on a collision course with the Supreme Court. The measure empowered California’s Democratic-controlled legislature to sideline the state’s independent Citizens Redistricting Commission and redraw congressional districts mid-decade. That commission, created by voters in 2008, was intended to curb partisan manipulation by placing map making in the hands of an independent 14-member panel focused on...