There will be a 30-day period for public comment before the commission takes a final vote on the plan.
The process to redraw the 203 House and 50 Senate district boundaries is supposed to reflect population changes documented by the once-a-decade census, but it is often fueled by politics.
The vote Monday was split along party lines. The commission's two Republicans, House Majority Leader Mike Turzai of Allegheny County and Senate Majority Leader Dominic Pileggi of Delaware County, supported the plan, while the two Democrats, House Minority Leader Frank Dermody and Senate Minority Leader Jay Costa, both of Allegheny County, opposed it.
Commission Chairman Stephen J. McEwan Jr., president judge emeritus of Superior Court and a Republican former Delaware County district attorney, cast the deciding vote.
Dermody and Costa blasted their Republican counterparts before the vote, saying that after months of negotiations they had only 30 minutes to review the final plans before they voted.
"This is not about fairness to the people of Pennsylvania, this is about maintaining a majority," Dermody said.
Turzai and Pileggi called the plan fair and said it met constitutional and statutory requirements.
"It addresses population shifts over the past 20 years," Pileggi said.
Costa said the plan was neither fair nor reasonable and did not accurately follow population changes.
"It was a raw, politically partisan exercise," he said.
Under the plan, the 169th District, which has been in Northeast Philadelphia and represented by Rep. Dennis O'Brien, a Republican, since 1977, would be moved to York County. The geographic area now represented by O'Brien would be absorbed by neighboring Philadelphia districts.
O'Brien is among five Republican candidates for City Council, but he said Monday he planned to keep his House seat if he lost.
He said he was surprised to learn his seat was being erased and did not think the population numbers supported the move.
"It's not good for the Northeast or the Republican Party," said O'Brien, who often votes with Democrats and other moderate Republicans from Southeastern Pennsylvania on legislative issues. "I know I'm not popular with my caucus, but my voice represents Northeast Philadelphia and Southeastern Pennsylvania."
Turzai said that while Philadelphia's population had edged up slightly since the 2000 census, it had not grown at the same rate as other parts of the state, particularly the northeastern and south-central areas.
"We couldn't justify not putting a seat in York," he said.
Fast-growing southern Chester County, specifically the Downingtown and Coatesville areas, would gain a House seat that would be shifted from a shrinking area in the southwest.
Democrats also criticized Republicans for what they said was a politically driven reworking of districts in Delaware County.
They said the plan reshapes Upper Darby's House and Senate seats to send neighborhoods with growing numbers of minorities, who tend to vote Democratic, into current Democratic legislative districts while preserving historically Republican districts.
In the House, Upper Darby, now split between one Republican and one Democratic legislative district, the 163d and 164th, would be carved up again, adding parts of the 166th, represented by Democrat Greg Vitali.
In the Senate it would shift GOP-dominated parts of the municipality into Republican Sen. Ted Erickson's district, the 26th, while sending Democratic neighborhoods into the Eighth District, represented by Democratic Sen. Anthony Hardy Williams, whose district is predominantly in Philadelphia.
Vitali and Rep. Margo Davidson, the first Democrat to represent the 164th District in many years, say their districts would be solidified with additional Democratic voters, while Republican Rep. Nick Micozzie's district, the 163d, would gain GOP voters.
"It helps the politicians and hurts the communities," said Vitali, whose hometown, Haverford Township, would be cut in two. "It clearly violates the constitutional provision to keep municipalities intact."
A hearing on the plan is scheduled for noon Nov. 18 in the Capitol's North Office Building.
Contact staff writer Amy Worden at 717-783-2584 or firstname.lastname@example.org, or follow her on Twitter @inkyamy.