HARRISBURG — The latest attempt to redraw Pennsylvania’s state legislative district boundaries for the first time since 2001 is headed back to the state’s highest court, which struck down a previous plan.

The state 20-member Senate Democratic minority caucus on Friday challenged the plan in state Supreme Court.

Meanwhile, another challenge is expected from an Allentown-area resident whose first lawsuit provided a crucial basis for the court’s earlier rejection.

Redrawing legislative districts is required by the constitution to account for population shifts over the last decade.

This year’s election was supposed to be based on a new plan.

But use of a new map will be delayed after the Supreme Court struck down a Republican-drawn plan in January, saying it contained unnecessary splits of municipalities and districts drawn into unusual shapes.