PA-12 is a rare example of “packing” (jamming as many opposition voters as possible into one district) that backfired. This district was created to be a Democratic stronghold formerly held by Congressman Jack Murtha, who was assumed to have a lock on the district. At the last redistricting in 2000, the Republicans in charge gave up on the area, which is solidly unionized, and decided to “pack” Murtha’s new district with as many Democrats as possible, to allow the remaining districts in the region a chance to have slim Republican majorities. But in the intervening ten years everything has changed: the area grew more and more conservative, and the locally popular Murtha died, opening up the seat to possible challengers. In the 2010 election, PA-12 barely remained Democratic with Mark Critz winning by a hairsbreadth 50.8%-49.2% margin — while most of the surrounding districts overwhelmingly went Republican. Thus, if the foolish 2000 Republican redistricters had not consciously set out to create a “packed” Democratic district, and had instead just drawn the boundaries at random, they could have easily won all the races in the area, instead of losing this one (and the adjacent PA-4) by the slimmest of margins. Note to gerrymanderers: THINGS CHANGE. What may appear to be a wise gerrymander maneuver today may blow up in your face sometime in the future.