Updated 3:40 p.m. ET: New Jersey Sen. Frank Lautenberg, D, won't seek re-election next November, a Democratic source confirmed to NBC News.

Lautenberg, the 89-year-old senator who served for almost two decades in the Senate from 1982 through 2001 before returning for a second term in the upper chamber in 2003, will not seek another six-year term.

"I will be traveling to my hometown of Paterson tomorrow to announce that I will not seek re-election in 2014.  This is not the end of anything, but rather the beginning of a two-year mission to pass new gun safety laws, protect children from toxic chemicals, and create more opportunities for working families in New Jersey," Lautenberg said in a statement. "While I may not be seeking re-election, there is plenty of work to do before the end of this term and I'm going to keep fighting as hard as ever for the people of New Jersey in the U.S. Senate." 

The decision clears the path for Newark Mayor Cory Booker to pursue the Democratic nomination for Senate. Booker, who's built a high national profile with his work as mayor, had provoked some public sniping from Lautenberg for seeming too quick to assume that the longtime senator would necessarily retire when his term is up in 2015.

Another Democrat thought to be eyeing the seat, Rep. Frank Pallone, effusively praised Lauternberg in a statement.

"I have peen proud to serve with Senator Lautenberg and even prouder to call him a friend," he said. "I look forward to continuing to work together in the coming months to continue to address the issues that are important to him and New Jersey.  Like all New Jerseyans, I am grateful for his service to our state and our nation."

Updated 3:40 p.m. --   Newark Mayor Cory Booker will pass on a challenge to New Jersey Republican Gov. Chris Christie, instead exploring a bid for the U.S. Senate seat currently held by Democrat Sen. Frank Lautenberg in 2014.

In a video posted to Booker's YouTube page, the mayor cites the need to "finish the work we have begun" in his decision not the challenge the state's popular governor.

"Let there be no doubt: I will complete my full second term as mayor of Newark, New Jersey," Booker says in the 3 minute video. "And as for my political future, I will explore the possibility of running for the United States Senate in 2014."

Booker's choice comes as no surprise to many observers, who have noted that Christie's popularity has surged to all-time highs in the wake of his response to Hurricane Sandy.

A spokesman for Lautenberg said Thursday afternoon that the senator will not address the 2014 election yet.

"This is not the time for political distractions and the Senator will address politics next year," said spokesman Caley Gray in a statement.

Lautenberg, who was first elected to the Senate in 1982, will be 90 years old in two years when his term is over. The 88 year-old New Jerseyan underwent treatment for a cancerous tumor in his stomach in 2010.

The news was first reported by WNBC.

The early returns are in, and the winner as the Democratic convention's most ubiquitous and energetic politician so far is Newark, N.J., Mayor Cory Booker. Seemingly everywhere you look, Booker is addressing a state delegation, speaking at a rally, or greeting his fans.

On Tuesday night as a summer storm boomed in Charlotte, Booker won thunderous applause as he addressed the convention on the platform.

"When your country is in a costly war with our soldiers sacrificing abroad, and our nation is facing a debt crisis at home, being asked to pay your fair share isn't class warfare, it's patriotism," he said, arguing the need for tax increases.

John Brecher / NBC News

Cory Booker, mayor of Newark, New Jersey, addresses the Florida delegation at the Democratic National Convention in Charlotte, North Carolina, on Tuesday morning.

But the mayor’s appearance on the dais was just his highest-profile one in a series of stops this convention week. On Tuesday morning, Booker brought the Florida delegation to its feet with a rousing speech.

“We can’t make the mistake that they (the Republicans) make of thinking this country is hungry for bash and slash and trash,” he said. “This country is hungry for hope.”

He got a huge laugh with his joke about New Jersey being superior to Virginia – despite the slogan, “Virginia is for lovers.” He said, “In New Jersey we invented the drive-in movie theater,” adding that his mother told him, “You were conceived in a double feature. Sidney Poitier, ‘In the Heat of the Night’ – and ‘Guess Who’s Coming to Dinner?’”

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Tuesday afternoon, Booker was the leadoff speaker at the Planned Parenthood Action Fund rally at the NASCAR Hall of Fame in downtown Charlotte. “He ran into a burning building to save a woman’s life,” actress and emcee Aisha Tyler said as she introduced Booker – a reference to his actions to save a neighbor from a fire earlier this year.

Booker told the crowd he’d made a mistake last week thinking he could do his usual late-night routine of simultaneously watching television and eating ice cream. While watching the Republican convention, he said he found that “Ben & Jerry does not mix with Mitt and Ryan ... that ice cream was curdling before I even got it to my mouth.”

He bashed New Jersey Republican Gov. Chris Christie – although not identifying him by name – for proposing a 2010 budget that cut funding for Planned Parenthood, resulting in the reduction of clinic hours.

“They may tell us they love women, but when they do things like that, they are setting all of us back,” he said. When a woman goes to a Planned Parenthood clinic, Booker said, “This is an opportunity for them to get contraception that could prevent the abortion that you are so much against.”

On Monday, Booker was up early to address the Iowa delegation where he got a wildly enthusiastic reception during his 25-minute speech and told that his grandmother was born in Des Moines, Iowa.

"My grandma back in 1918 was born in Des Moines, Iowa ... My grandmother grew up there, my grandmother's siblings went to college there. My family is still spread out all through Iowa ... I'm proud, proud of those roots," he said.

Booker told the delegates that great-grandparents moved from Alabama to Buxton, Iowa which in the early 1900s was a big coal mining town with a large African-American population. Booker’s mention of Buxton got a big round of applause. "Some people know what I'm talking about!" he said.

John Brecher / NBC News

Cory Booker, mayor of Newark, New Jersey, addresses the Florida delegation at the Democratic National Convention in Charlotte, North Carolina, on Tuesday morning.

Related: Iowa Democrats prepare for starring role in fall campaign

It’s not clear where Booker’s relentless energy will lead the mayor electorally. Two possible opportunities await back in his home state: to run for senator if Sen. Frank Lautenberg, D-N.J., decides to retire in 2014, or to run for governor next year against Christie.

“I think even he may not know yet,” said David Redlawsk, director of the Rutgers-Eagleton Poll and professor of political science at Rutgers University in New Jersey. “He's ambitious, but ambition in New Jersey usually runs up against various power brokers. I don't think he'd want to take on Lautenberg in a primary, so the Senate depends on what the current senator decides to do. He has, of course, insisted he will be running again.”

Redlawsk added, “Governor is also tricky, given that Christie's ratings have held up, and that right now you'd have to say he has the inside track for a second term. A loss to Christie would certainly be painful. The Senate seat is far more likely to stay in Democratic hands than Christie is to lose at this point. Thus, if Booker could somehow clear the decks for a Senate run, and Lautenberg retired, that would give him the highest probability of success.”

No matter how high he is able to climb in New Jersey politics, Booker is tirelessly building a national following here in Charlotte – and on Thursday he'll be addressing the New Hampshire delegation's breakfast. 

Mayor Cory Booker of Newark, N.J., spoke out in support of Mitt Romney's experience at private equity firm Bain Capital. NBC's Peter Alexander reports. 

Newark Mayor Cory Booker released a video on Sunday emphasizing his support for President Obama's re-election after condemning some the president's re-election tactics as "nauseating."

Booker said in a video posted to YouTube that he believed it was appropriate to fully vet Mitt Romney's private sector record, clarifying his head-turning comments this morning on "Meet the Press," on which he decried the Obama campaign's attacks on Romney due to an instance in which a company acquired by Bain Capital, which Romney cofounded, ended up in bankruptcy.

"This kind of stuff is nauseating to me on both sides. It's nauseating to the American public. Enough is enough. Stop attacking private equity, stop attacking Jeremiah Wright," Booker said during a roundtable on the program, referencing also the plan mulled by a Republican super PAC to link the president to a controversial pastor. 

The remark was a badly off-script tangent for Booker, who's regarded as a rising star within the Democratic Party, and an effective surrogate for Obama. The president's re-election campaign had worked all week to drive a message painting Romney's experience at Bain as primarily motivated by profits at all costs, rather than the expertise on job creation that Romney has sought to project. 

Booker's video, released late Sunday afternoon, doesn't renounce his comments made on "Meet the Press," but it does describe the Obama campaign's scrutiny of Romney's business record as appropriate. 

"I made it clear on 'Meet the Press' this morning how I feel President Barack Obama has done such a strong job as leader of our nation, and more than deserves re-election," Booker said. 

"I also professed, on 'Meet the Press,' my profound frustration with the kind of campaigning that I think that is becoming too much of the norm in our nation — which is generally negative campaigning. And this campaigning is about to become an avalanche, and in many ways, I believe, could potentially risk muting out the important voices of the candidates themselves talking about the issues that matter," he added, referencing the millions spent by outside super PACs on campaign advertising. 

And of Romney's Bain record, Booker said: "Let me be clear: Mitt Romney has made his business record a centerpiece of his campaign … and therefore, it is reasonable — and in fact, I encourage it for the Obama campaign — to examine that record and to discuss it. I have no problem with that."

Mayor of Newark, N.J., Cory Booker, Republican strategist Mike Murphy, CNBC's Jim Cramer, and the Wall Street Journal's Kim Strassel weighs in on the campaigns, economic worries, battling on capitol hill and other issues of political merit.

A new viral video starring New Jersey Gov. Chris Christie and Newark Mayor Cory Booker (a potential future rival of Christie's) helps underscore the value for politicians in being able to navigate new media and contemporary culture.

The video, released on Tuesday night by Christie's office, shows Booker, the Democratic mayor popularized for his antics of shoveling snow or rushing into a burning building to save a neighbor, running to the rescue every time the Republican governor encounters a mishap. But when Booker is facetiously shown talking to Mitt Romney about a spot on the Republican ticket, Christie intervenes.

The skit was produced for a legislative correspondents' dinner along the line of the White House Correspondents' Association gathering hosted every year in Washington and was quickly passed around.

Humor has always been a part of the modern political campaign -- think Richard Nixon's appearance during his run for president on the television show "Laugh-In." But humor's role has been augmented in the age of social media and viral videos; candidates and politicians, at a bare minimum, now try to show that they’re at least conversational in the language of pop culture and sufficiently self-effacing.

“The Christie video gets the No. 1 rule of political humor: It’s an incredibly powerful weapon, but in order to be able to wield it against others, you have to be willing to turn it on yourself first,” said Jeff Nussbaum, a partner at West Wing Writers, who’s worked on political humor for Democratic candidates and officeholders.

“I think that, more and more, people not only want their elected officials to have policy positions, but they also want these people to be relatable,” he said. “And humor is an incredibly good way for elected officials to show they can relate, laugh and, more importantly, laugh at themselves.”

Humor falls along the continuum of reliability, a trait on which every political candidate hopes to trade.

That broader sense of cultural versatility explains why President Barack Obama drew wild cheers from the audience of ABC”s “The View” when he correctly named which of the Kardashian sisters had divorced her husband 72 days. And it’s why Obama, a few weeks earlier, chose to
participate in a “Slow-Jamming the News” skit on NBC’s “Late Night with Jimmy Fallon.”

Sarah Palin’s 2008 appearance on “Saturday Night Live,” alongside parody-doppelganger Tina Fey, served many of the same purposes; it’s why Mitt Romney still might appear on the same show this fall.

Nussbaum suggested, too, that Obama’s use of humor has been most effective in deflecting his fiercest criticism, for instance, his jokes about the origin of his birth certificate in light of public scrutiny from Donald Trump.

But employing humor or trying to seem pop-culture savvy has its limits, and might not work the best for some candidates. It depends on the circumstances.

“When I first saw it, I asked myself, 'Hmm, I wonder if Mitt Romney should do something like that?'” said Republican ad man Fred Davis, who concluded that the presumptive Republican presidential nominee would be served better by a sober campaign emphasizing his competence versus Obama.

“I think most of Romney's attempts at humanizing himself have fallen a little flat,” Davis said. “Romney's path to victory is probably not being funnier than Obama on Letterman; his path to victory is being more competent than Obama.”

(“I’ll say this: I’m not eager to see Mitt Romney at an open mic night anytime soon,” Nussbaum said.)

The risk, though, always involves the humor hitting too close to home.

Some believe Al Gore’s frequent jokes about his stiffness as a candidate reinforced an existing public perception. And President George W. Bush’s jokes about being able to locate weapons of mass destruction in Iraq came against a backdrop of bloodshed in that war, which was heavily predicated on the purported existence of those weapons.

But if Christie has serious designs on getting a vice presidential nomination, the video may have hurt those chances as much as helped.  Christie’s video mentions -- twice -- his status as a favorite pick to round out Mitt Romney’s ticket, including the video’s biggest comedic payoff at the end.

“I think it maybe went one click too far in that direction, but I don’t think it crossed the more dangerous thresholds for humor,” Nussbaum said.

And Davis, whose ad firm has earned a reputation for its eyebrow-raising humor, said he far prefers to invoke laugh lines when going after other candidates.

“We're really big on humor. But where it plays the biggest role is in making an attack where that doesn’t blow back against the attacker,” he said.  “Emotion works in advertising, and humor is a very powerful emotion.”