The 2012 Presidential election in the 2022-2032 NJ-07th CD, Mitt Romney's second best congressional district in the state (NJ-04 was won by him by 17.2%) would be one to bolt left during the Trump Era, eventually voting for Biden by 3.7%
Here, Romney performed as well in the afluent suburbs of the district in Somerset Moris and Hunterdon counties as he did in the rural and working class Warren and Sussex counties
Both of these margins combined, however, heavilly overpowered the deep blue Rahway and Linden. It should be noted that despite improving on McCain's '08 margin in the seat, Sandy likely raised Obama's floor in the seat.
Heading into 2016, the major signs of slippage would be seen in this seat, with Democrats improving in the Somerset Morris & Union Portions of the seat as controvercial GOP candidate Donald Trump accelerated a trend in suburban republicans leavind the party
While Clinton lost this seat by 6%, she improoved on Obama's 11% loss by just over 5%—an improvement tapered by the working Class Warren and Sussex bolting right in the 2020 election.
Alongside Cory Booker who won it by a hair, President Joe Biden would become the first democrat in the modern Era to win the seat in the 2020 presidential election, improving throughout the seat,
even if he lost ground compared to Clinton and Obama in the Minority heavy Rahway, Linden and Clark portions of the seat, mostly due to significant slippage among hispanic voters.
The 2012-2022 Swing maps highlight the changing partisan compositions of this seat, as Biden compared to 2012 lost ground in the minority heavy Linden & Rahway and most of the working class portions of Sussex county.
However, this had a negligible impact on the district as a whole compared to Obama.
Here, instead, on the backs of upscale college educated suburbanites, Biden improived throughout most of the districts, especially in Warren township, the Mendhams, and the suburban western Union Suburbs
Combined, these three swings present a major problem for Tom Kean Jr, as the smallest of all of them in this seat (the 5% swing between Obama and Clinton) would place the seat at just over an 8% Biden win,
This then combines with Congressman Kean's underwhelming performance against Tom Malinowski in 2022—compared to his 2020 performance—to place him in a tough position where he will need to fight to retain his seat, as the underlying trends here are not in his favor.