It only took three years for Pennsylvania’s 12th District to go from a safe Democratic seat to a safe Republican seat.

The legendary late Rep. John P. Murtha, a Democrat, represented the district for more than 30 years, but his tenure also masked a cultural shift in southwest Pennsylvania. Even though Democrats were able to hold the seat briefly after his death, Republican-led redistricting helped pull this seat into the GOP column, where it looks like it will remain for at least the near term.

Democrat Mark Critz, one of Murtha’s top aides, won a high-profile special election in May 2010 and was re-elected that November. But GOP legislators subsequently made the seat more Republican and Keith Rothfus defeated Critz, 52 percent to 48 percent, in 2012.

Critz’s showing was remarkable considering President Barack Obama earned just 41 percent against Mitt Romney in the last presidential election. That also demonstrates the challenge any Democratic nominee will have next year.

Democrats had hoped Critz would run again in 2014, but he opted to run for lieutenant governor instead. Now Democrats are looking to 79-year-old retired Marine Colonel John Hugya to take the seat back.

Hugya didn’t just parachute into the district; he was Murtha’s long-time aide and chief of staff. Psychologist Erin McClelland is also running, but doesn’t appear to have attracted the attention of Democrats in Washington, D.C.

It’s possible that this develops into a Democratic target. But since Republicans have carried redrawn seat by an average of 11 points in the past three presidential elections, it’s a tough place to start. And it’s more likely that seats in southeast Pennsylvania become more competitive before this one.

Pennsylvania’s 12th District is now rated Safe Republican (from Republican Favored) by Rothenberg Political Report/Roll Call.