TRENTON, N.J. (CBSNewYork/AP)Lawmakers from both sides of the aisle have been offering their condolences and praising the career of longtime Sen. Frank Lautenberg (D-N.J.), who died early Monday at the age of 89.

Lautenberg’s term was due to end next year. Now, it will fall to Gov. Chris Christie to appoint a replacement to fill Lautenberg’s vacant seat. Christie had kind words to say about the senator’s passing even though the Republican governor and the fiercely  Democratic senator didn’t see eye to eye.

“It’s probably more honest to say we didn’t often agree  and we had some pretty good fights over time,” Christie told reporters, including  CBS 2’s Marcia Kramer.

Christie could appoint a member of his party to fill the seat, which has been in Democratic hands for three decades.

Democratic State Senate President Steve Sweeney said the seat should go to a fellow Democrat.

“The governor should put a Democrat in the seat, that’s who won the seat,” Sweeney told WCBS 880’s Jim Smith. “People didn’t elect a Republican in that seat, they elected a Democrat.”

But Sweeney added he has no expectation that Christie will appoint outside his own party.

Associate Director of the Rutgers Eagleton Institute Of Politics John Weingart said there is no chance Christie will cross party lines. Weingart called the open seat an opportunity for Republicans.

“To be better known across the state and be able to run for a full term as something of an incumbent,” Weingart told Smith.

EXTRA: Friends, Colleagues React | Notable Deaths 2013

Weingart noted it’s a complicated equation since Christie would have to pick a politician moderate enough to win the election in 2014, but not so moderate as to draw backlash from the national GOP.

Political consultant Hank Sheinkopf more or less agreed.

“Governor Christie has to pick a Republican. Why? National Republicans will say wait a minute he’s too close to President Obama. He’s got to strengthen his party credentials if he wants to be a national player and apparently he does,” Sheinkopf said.

Christie has been mentioned as a possible 2016 presidential candidate, but has drawn the ire of his own party for his praise of President Obama’s handling of the aftermath of Hurricane Sandy.

Newark Mayor Cory Booker had pondered a potential run to challenge Christie for governor, but announced earlier this year he’d seek Lautenberg’s Senate seat. Booker has already raised $2 million for his Senate bid.

The leading GOP contenders would be his lieutenant governor, Kim Gaudagno, state Sen. Tom Kean Jr., the son of the former governor, and Joe Kyrillos, a close Christie confident who ran for Senate — and lost — in 2012, or Christie Todd Whitman, Kramer reported.

There will be major pressure to stay with his party because adding a Republican seat in the Senate — and subtracting a Democrat — could change the Washington dynamic.

“It could have profound consequences,” Baruch College professor Doug Muzzio said.

And then there’s the so-called “Stone Pony” choice.

“My personal favorite is he appoints Bruce Springsteen and everybody’s happy,” Muzzio said.

Christie has been polling strongly over Democratic challenger Barbara Buono as he seeks re-election this November.

Christie will appoint a successor and then could hold a special election to determine a replacement for the remainder of the term.

It’s not clear when the state’s voters will get a say. Two state laws govern when a special election should be held to fill a vacancy.

The possibilities seem to be regularly scheduled election days in November, June 2014 or November 2014, or some other date chosen by the governor. A court may be asked to decide which law applies and how to interpret it.

“We don’t know much given the murkiness and ambiguity of New Jersey state law. Everybody’s at their law offices now trying to figure out the law,” Muzzio said.

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