(Andrew Harrer/Bloomberg)

The president announced his support for Rep. Steve Rothman (D-N.J.) Friday, in his bid to defeat Rep. Bill Pascrell (D-N.J.) in a bitter congressional primary set to be one of the closest in Garden State history.

Taking full advantage of the presidential perks he can share with political allies, Obama invited Rothman Friday to the Oval Office for a private meeting, where he announced he’s backing the lawmaker’s bid.

Why is the president wading into congressional politics — and into one of the most nasty “member vs. member” primaries of the year? Because Rothman was the only New Jersey Democratic lawmaker to endorse Obama’s 2008 presidential campaign when Pascrell and other New Jersey Democratic pols backed Hillary Rodham Clinton.

“I think it’s fair to say that he was not unmindful that appearing with me as we walked along the White House colonnade in full view of the entire White House press corps might very well make into the New Jersey newspapers,” Rothman said after his White House meeting.

In an early sign of White House support, Obama adviser David Axelrod appeared last week alongside Rothman and said “loyalty” was the reason he was backing the lawmaker.

But Obama’s endorsement now pits him against former President Bill Clinton, his occasional political partner who has appeared at campaign fundraisers and authored supportive campaign e-mails to supporters.

The former president is campaigning Friday with Pascrell for the second time. Why? Because Pascrell backed the former first lady’s presidential bid four years ago.

In an interview, Rothman said Axelrod and Obama’s support “is certainly helpful to remind Democrats that I was the only member of Congress from New Jersey, the first in the Northeast, to endorse Barack Obama for president when the entire New Jersey political establishment had endorsed Hillary.”

Pascrell, who later endorsed Obama, said in an interview that he appreciates Clinton’s support — but thinks the primary fight with Rothman could damage Obama’s electoral chances.

Pascrell, 75, and Rothman, 59, were both elected to the House in 1996 and became close friends as they rode the train together to Washington and shared dinners fueled by red wine and cigars. They even appeared as subjects of the popular “Better Know a District” segments on Comedy Central’s “The Colbert Report.”

But New Jersey is losing one of its 13 House seats and a redrawn congressional map split up Rothman’s turf between Pascrell’s district and an area represented by Rep. Scott Garrett (R-N.J.). Pascrell and Rothman are now fighting to represent a slice of New Jersey that stretches from the George Washington Bridge to Giants Stadium and parts of densely-populated Bergen, Hudson and Passaic counties. (Parts of the new district appeared prominently in the opening credits of HBO’s “The Sopranos” — a show whose depictions Pascrell once strongly denounced.)

“I have been the reliable progressive vote,” Rothman said Thursday. “In addition, because of my position on the House Appropriations Committee, I’ve brought home more than $2.2 billion for vital projects at home, which not only allowed for that work to be done, those jobs to be created, but also prevented the local property tax payers from having to foot the bill for that work.”

Pascrell is clearly miffed by his former friend’s decision to run against him instead of challenging Rep. Scott Garrett (R-N.J.), a tea party-backed lawmaker whose district swallowed up a good portion of Rothman’s former territory.

Rothman “chose to move, come into my district, rather than fight Scott Garrett,” Pascrell said Thursday. “He claims to be a progressive? That’s not very progressive – jumping out of a fight with Scott Garrett. He’d rather fight against his ‘friend’ Bill Pascrell. We’re supposed to be winning back the majority in the House.”

Veteran New Jersey political observers expect Tuesday’s results to be some of the closest in state history. Whoever wins should easily cruise to reelection from the reliably Democratic district. But now a bitter personal political feud has caught the attention of the current and former president — and puncture holes in their fragile relationship.

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