HARRISBURG — A new map of Pennsylvania’s U.S. House districts drawn by Republicans would make it harder, but not impossible, for Democrats to win more seats in the state, Democratic campaign strategists said Monday.

The proposal, designed to ensure that the majority of the state’s U.S. representatives are Republicans, would eliminate a southwestern Pennsylvania seat held by a Democrat and shift tracts of Democratic-leaning voters, such as the cities of Scranton and Wilkes-Barre, from swing districts to districts where they are less likely to defeat Republican incumbents. Meanwhile, Republican-held eastern Pennsylvania districts in increasingly liberal areas would stretch deep into central Pennsylvania to pick up more conservative voters.

For one thing, the redrawn map would put more pressure on Democrats to recruit top-notch candidates, particularly in years where the political atmosphere favors Democrats. Turnout is expected to be strong in next year’s presidential election, which Democrats say will help their candidates.

“There is some path to victory, it’s just an uphill battle,” said Mary Isenhour, the former executive director of the Pennsylvania Democratic Party. “And unless you have the ideal candidate with enough money, it’s not competitive.”

Currently, Pennsylvania has 12 Republican U.S. House members and seven Democrats.

In northeastern Pennsylvania, freshman Republican Lou Barletta would shed the heavily Democratic cities of Scranton and Wilkes-Barre. Democrats currently hold a 57 percent to 31 percent registration advantage in his 11th District, but the proposal would nearly even out registration between Republicans and Democrats.

Republican Charles Dent in the 15th District would no longer represent the city of Easton, helping him halve a 13 percentage point gap between Republicans and Democrats.

Meanwhile, Democrat Tim Holden in the 17th District would pick up all three cities, transforming his district from one where Republicans outnumber Democrats by 4 percentage points to one where Democrats dominate, 56 percent to 32 percent.

In the Philadelphia suburbs, Republican Jim Gerlach’s 6th District seat would flip a Democratic registration advantage of about 5 percentage points. Meanwhile, the 7th District, represented by freshman Republican Pat Meehan, would add tentacles into two new counties so that it could become a majority Republican district.

On Monday, Republicans defeated Democratic attempts to make changes to the bill containing the redrawn districts during floor debate in the state House of Representatives. A final vote was expected today before the bill can go to the desk of Gov. Tom Corbett for his signature. The map, drawn in private by top state Republicans, was unveiled last week and narrowly passed the Senate on Wednesday night.

A new congressional map is required every decade to reflect population shifts. Because Pennsylvania grew more slowly than the rest of the nation, it will lose a U.S. House seat, dropping from 19 to 18 in the 2012 election and ensuring significant changes.

Those once-a-decade changes are being controlled this time around by Republicans, since they control the state Legislature and the governor’s office.