This traditionally Republican district in northeastern Wisconsin has been held by a Democrat for three consecutive terms only once -- during the great GOP/Progressive schism of the early 1910s. Democrat Steve Kagen thought he might have a chance at doing so, but ended up losing by 10 points in the GOP landslide of 2010.
The winner of that race, businessman Reid Ribble, has kept a fairly low profile in Washington. He's made some of the usual GOP mistakes such as calling Social Security a "Ponzi scheme," but managed to avoid a top-tier challenger. The GOP lean of the district means that, absent a sudden collapse by the Romney campaign, Ribble is unlikely to lose.