The 2012 Democratic Primary in the Ninth Congressional District, an urban smackdown between Incumbents, Paterson's Bill Pascrell, and Englewood's Steve Rothman resulting from a redistricting that combined the 2010s NJ CD-08 and CD-09.
It is well known that incumbent on incumbent Primaries tend to be cold-blooded and vicious affairs, but the Ninth's primary, which began with both incumbents professing their friendship, devolved into calls of Cowardace and mockery
While redistricting had drawn Paterson, and the core of Pascrell's old CD-08 into CD-09, it also drew Rothman's home in Fair Lawn New Jersey into the at the time conservative CD-05 held by Arch Conservative Republican Scott Garrett
In this sense, the NJ Redistricting Commission had set a battle between Garrett & Rothman, a fight many democrats, including Pascrell, former Speaker Nancy Pelosi, and DCCC chair Steve Israel, wanted Rothman to take.
However, Rothman, seeing it as a futile battle against a "Republican Gerrymander" challenged Pascrell to save his political career. Funcionally arguing that he was following his constituents, as he had represented most of the district at one point or another.
It should be noted that in 2012 while Garet won the seat by 13.2%, Romney only won the Seat by 3%, and Menendez won it by 0.5%.
Nonetheless, Rothman Challenged Pascrell. Handicappers early on noted that Rothman had the advantage, as he had represented over half of the District, had the line in Bergen and Hudson Counties, and Pascrell's home town of Paterson tended to have low voter turnout.
Despite this, it was seen as either man's game throughout the campaign.
The NJ Star Ledger noted that while they were not thar far off Ideologically, their styles reflected their hometowns, with Pascrell showcasing more of a blue collar style and Rothman a Wealthy White Collar one.
During the campaign Pascrell Played up Rothman's carpetbagging, calling him a chicken for not challenging Garrett, and setting up a website to deliniate how many days it has been since Rothman hadn't moved to the District
Further, both tried to enphasize their ties to the district, with the NYT highligting an anecdote where both congressmen—Honoring Cliffside Park's Gerald Calabrese, the longest serving NJ mayor at the time—enphasiized their connections to Calabrese.
Rothman had mentioned that he had known the mayor since his days in the young Democrats, and Pascrell noted that he had known Calabrese's father back in the day.
Further, Both members tried to emphasize their committee assignments, with Rothman highlighting that his position on the House appropriations committee would allow him to bring back Pork to the 9th, Pascrell countered by highlighting that he was on the Ways and Means committee.
Moreover, the race had partially become a 2008 primary proxy battle, with Bill Clinton endorsing Pascrell for his support for Hillary in 2008, and Obama supporting Rothman through David Axelrod & a "much-publicized Oval Office visit several days before the primary" (Politico)
It should be noted that the Issue of Israel played an issue here, with Rothman (a member of the Jewish faith with a Pro-Israel Record) being endorsed by Orthodox groups in Passaic City & Englewood, and Pascrell inversely supported by the district's Arab-American Community
In the end, Pascrell won. Beyond the campaign mentioned above, the factor that clinched the race for him was that his voter turnout operation, which made it so the Passaic portion—which had 44.96% of the population—comprised 54.45% of the Electorate, winning it by an 80.7% Margin
This compared to the Bergen and Hudson County sections which comprised 45.55% of the vote, 55.04% of the Population and which Rothman won by 47.04%.
Special thanks to @HWLavelleMaps for getting me this data!