The U.S. Supreme Court has said that under the one-person, one-vote principle, all election districts must have close to the same size of population. A group representing Latinos joined the suit, saying their numbers had increased by a wide margin across the state since 2001 - by 45 percent in Philadelphia.
The issue of old maps arose after the Pennsylvania Supreme Court, by a 4-3 vote, rejected a plan that would have brought maps up to date to reflect the 2010 census.
The state court said the plan by a Legislative Reapportionment Commission - criticized by Democrats as heavily gerrymandered - did not pass state constitutional muster. It said the plan improperly broke up counties, municipalities, and Philadelphia wards that should have been kept in single districts unless "absolutely necessary."
Republican leaders said Wednesday that they hoped the five-member commission could vote on a new plan Feb. 22.
Democrats argued, however, that it was too late for the primary. A new plan, a public comment period, and an appeal period would take from 90 to 120 days, they said.
The deadline for primary candidates to file nominating petitions is next Thursday.
Surrick rejected a request from Senate Majority Leader Dominic Pileggi, House Speaker Sam Smith, and House Majority Leader Mike Turzai, among others, to issue a temporary retraining order against the old maps.
He also declined a request for a three-judge panel to take a longer look at the case.
"To enjoin the 2012 election from proceeding under the 2001 plan would leave the Pennsylvania primary in a state of unacceptable uncertainty," he said.
Surrick noted that with presidential and congressional balloting this year, the issue was of concern beyond Pennsylvania.
