Rep. Jim GerlachJames (Jim) GerlachPa. GOP 'disappointed' by rep retiring after filing deadline Pennsylvania Republican Costello won't seek reelection Republican Pa. congressman won't seek reelection: report MORE (R-Pa.) announced Monday he won't run for reelection, opening up a potentially competitive swing seat as another centrist Republican heads for the exits.


"It is simply time for me to move on to new challenges and to spend more time with my wife and family," Gerlach said in a statement. "This is a tremendously difficult decision because I have had the opportunity to work with a multitude of dedicated public servants throughout the years. Together, we have worked to strengthen our communities and create opportunities for the hard-working families we have been privileged to represent."


The six-term incumbent had long been Democratic target, and they now see a prime pick-up opportunity while Republicans are on the defensive.


Gerlach's Eastern Pennsylvania district was made safer for the GOP after redistricting but is still winnable for either party. Mitt Romney won the 6th District with 51 percent of the vote in 2012 but President Obama carried it in 2008.


Potential Republican candidates for the seat include Chester County Commissioner Ryan Costello, GOP County Chairman Val DiGiorgio, former Senate and gubernatorial candidate Sam Rohrer and Pennsylvania state Sen. John Rafferty. Rohrer, who has close ties with the Tea Party, could pose a problem for establishment Republicans in the district, according to observers.


Businessman Michael Parrish had already filed against Gerlach, and Democrats consider him a strong candidate.  Other Democrats who might be interested in the seat include Manan Trivedi, who lost to Gerlach in 2010 and 2012, state Sen. Judy Schwank, and Sen. Bob Casey's (D-Pa.) brother Chris Casey, who Democrats have tried to recruit to run in previous years.


"As long as Jim Gerlach was the candidate Republicans were going to hold that seat," said Pennsylvania-based political observer Keegan Gibson. "With Gerlach out of the picture, that changes everything... This is a right down the middle seat, and if Democrats recruit a strong candidate it's definitely in play."


Gerlach’s retirement doesn’t mean he’s done with politics for good, but he is this year at least. Gerlach briefly ran for governor in 2010 and been mentioned as a potential primary challenger to vulnerable Gov. Tom Corbett (R).


"Jim's not running for office in 2014. He's not ruling out public service in the future but at this point he's looking for some new adventures and spend some well-deserved time with his family," said Gerlach advisor Vince Galko.


Gerlach is only the the latest swing-district Republican whose retirement has given Democrats an opportunity and caused GOP headaches.


Reps. Tom Latham (R-Iowa), Frank Wolf (R-Va.), Jon Runyan (R-N.J.) and Tim Griffin (R-Ark.) have all decided to leave Congress after this term, giving Democrats better shots at their seats, and Rep. Bill Young's (R-Fla.) death has given Democrats an additional opportunity in March’s special election.

Democrats said the retirement was a sign of dwindling centrist support for the GOP, while Republicans predicted they'll hold the seat.

"I join with my colleagues in wishing Jim and his family well in this new chapter in their lives. Though we are losing a strong advocate for Pennsylvania, I have no doubt we will elect another Republican leader in November who will be the same thoughtful lawmaker that Jim is," National Republican Congressional Committee Chairman Greg Walden (R-Ore.) said in a  statement.


"As these Republicans jump ship, Democrats’ battlefield for 2014 continues to expand," Democratic Congressional Campaign Committee Chairman Steve Israel (D-N.Y.) said in a statement. "Republicans now have to defend this competitive district because the Democratic candidate will be committed to strengthening the middle class, focusing on job creation and taking commonsense steps like increasing the minimum wage, while the Republican candidate will be beholden to the same type of Republicans who now run this dysfunctional Republican Congress."

—This post was last updated at 3:55 p.m.