During Saturday’s events for the 50th anniversary of the March on Washington, Cory Booker dabbed his dome with a white handkerchief on the steps of the Lincoln Memorial and bellowed, “We still have work to do.” The next morning, the mayor of Newark appeared as a guest on NBC’s “Meet the Press” and bemoaned “too much division going on in our politics.”

Booker is no stranger to Washington. His parents met here. He was born here. He spent his Christmas breaks from Oxford here. Now a political sensation and media darling with nearly 1.5 million Twitter followers, the 44-year-old seems to have been engineered in a political lab to walk the halls of Congress.

Unless something implausible happens — specifically, an unknown tea party candidate named Steve Lonegan wins statewide office in New Jersey — Booker will return to Washington this fall as the state’s junior senator and a regular in the presidential and vice presidential sweepstakes. Fresh off a convincing victory in the Democratic primary for the seat that was held by the late Sen. Frank Lautenberg, also a Democrat, Booker acknowledges that the race is his to lose. He is prepping for the eventual move to the capital with a nightly audio book appointment with “This Town,” the bestseller by New York Times reporter Mark Leibovich that paints an unflattering portrait of official Washington.

“I fell asleep to it last night,” Booker says a few hours after receiving an endorsement from President Obama, a friend to whom he is often compared. “I love to see the cognitive laziness — that is, cynicism — at its best.”

Booker, a husky vegetarian who would be the only black Democrat in the Senate, is draining Splenda-sweetened coffee at a Greek diner in Union, just outside of Newark. He talks a lot about cynicism, calling it, “the most cognitively debilitating state of being” and declaring that “my whole life has been about confronting cynicism.” The point is that in a cynical world and a paralyzed Washington, Cory Booker is going to be different. He is going to change things.

Just don’t ask what, or how.

It is something of a mystery what kind of a senator Booker will try to be. Conservatives fear he will be a liberal lion. Liberals fear a Trojan horse for Wall Street and Silicon Valley interests. His detractors see him as an insatiable political animal who, in pursuit of his own national prospects, is willing to compromise on Democratic ideals and continue boosting his mutually beneficial relationship with New Jersey Gov. Chris Christie, who is a potential Republican presidential nominee. Booker is cagey about whether he aspires to be the next Sen. Ted Kennedy, but there is no doubt that he would be the chamber’s Senator TED Talk.

“People are always trying to draw simplistic dialectics that can capture things,” he says when asked if he plans to be a workhorse or a show horse. “Putting aside the fact that there is a difference between popularity and purpose and celebrity and significance, the most important thing to say is first, you’ve just got to confess that I don’t know.”

Booker emphasizes the work he would be doing with the poorer parts of New Jersey and his ability to “call up companies and say, ‘This is a moral sin’ ” or “call together some of our brightest tech minds and say, ‘How do we give greater transparency into how a bill is made a law?’ ” But, legislatively, he insists he doesn’t “have the script or even the codified strategy yet. I just know that I’m innovative. I’m a quick thinker. . . . In Washington, I just want to be a senator who finds a way to drive change and not figure out a way to conform.” He promises to be “fiercely myself.”

The search for Cory Booker’s true self has enthralled New Jersey since he came to Newark’s city council in 1998. He became a national star after filmmakers documented his losing campaign for mayor against Sharpe James in 2002, a race in which James famously called him “a Republican who took money from the KKK Taliban . . . [who is] collaborating with the Jews to take over Newark.”

Booker won the office in 2006, but his lore — and his political travel — extends beyond Newark, where his record is hotly debated. Some people drop names; Booker drops past exploits. For instance, he happened to be on “the only team that ever won the state championship from my high school.” He touches on his football stardom at Stanford by saying, “I am a geek nerd who happened to have a temporary period of jockiness.” Obama gave him a ring “when I had the incident with the fire,” meaning the time he rushed into a burning building to rescue a neighbor. He observes that while some of the New York mayoral candidates have talked about how they spent a night in a housing project, “I spent eight years living without heat and hot water.” When talking about the things he does quietly, he lets slip the time in college when he talked a jumper off a ledge “in front of the entire campus.” He’s not worried about missing Newark because Congress is hardly ever in session and “the longest vacation I took was one for my 40th birthday — 10 days.”

He is partial to quoting Winston Churchill and using rhetorical flourishes, such as “Touché, mon capitaine.” He says goodbye to the diner owners in Greek, chats with an Ecuadorean patron in Spanish and wishes a Jewish reporter happy holidays in Hebrew.

Cory Booker, in other words, can talk to anyone. He rarely misses an opportunity to point out that he and Christie — two of the most talented and quick-on-their-feet politicians in the country — have worked together to bring development and jobs to Newark. And he says he has a similarly strategic alliance with George Norcross III, a controversial former Democratic political boss, who, a few weeks ago, asked Booker to appear at a charity comedy event sponsored by the Philadelphia Daily News, which he owns.

“I asked him about doing it,” Norcross says. “And the following day he said, ‘Terrific.’ ”

On Wednesday night, Booker crosses the state line in his SUV to attend the comedy show on the top floor of Finnegan’s Wake, a brick-walled pub in South Philadelphia. The dozen or so tables set aside for local politicians and donors to a children’s charity slowly fill up as waitresses deliver bottles of beer and gin and tonics in clear plastic glasses. Booker enters, pauses for photos and grips a bottle of water. He looks around in disbelief through an hour of stripper, Viagra and masturbation jokes but perks up when Philly’s District Attorney Seth Williams begins a riff on the prodigious Twitter account of “Pennsylvania’s future third senator” — shorthand for Booker.

“It’s been a full-time job for me just keeping up with him,” Williams says. “He’s tweeting every, what, 20 seconds? . . . It’s like every other second, he saved a woman out of a burning house. He was in a helicopter and went down in raging waters during superstorm Sandy. There was a panda where a train fell over at the zoo. He got the panda inseminated, all types of stuff. He is a true hero. Hero!”

Finally, Booker takes the stage. He stands in front of the brick wall and notes that “I’ve never ever been accused of inseminating a panda before tonight. . . . My staff literally said, ‘Let’s get out of here.’ ” He tells some safe, crowd-pleasing sports jokes and attributes his presence in a state absent of Jersey voters to his “perfunctory profession of prodigious pandering.” He jokes about the triteness of comparisons with Obama. “President Obama left school to become a community organizer. I left school to become a neighborhood coordinator. . . . President Obama was born in the United States of America, I was born in Washington, D.C.”

Booker, who left D.C. as an infant for a wealthy Jersey suburb, says he is going to call attention to the plight of the District’s dis­advantaged by living in a part of Washington “consistent with the choices of my lifetime” (read Anacostia). This will all focus media attention on Booker and his cause, but it’s not obvious how any of this translates to the Senate.

There are generally two paths for first-term celebrity senators. One is avoiding the aura of showboating by keeping his or her head down, such as Hillary Clinton, Al Franken and Elizabeth Warren. The alternative route — especially in a paralyzed chamber — is to seek immediate impact through speeches and agitation, if not by passing legislation. Some people have tried to predict Booker’s approach by citing his public admiration of Republican senators Rand Paul (Ky.) and Ted Cruz (Tex.) (“I did it in one or two interviews, which I’ve now been told not to do. But I picked them because they are in people’s minds as the impossible people to deal with.”)

For now, Booker prefers to underscore areas of common ground with Republicans who are interested in overhauling the prison system or bringing more transparency to the National Security Agency. He is less interested in talking about his positions on overhauling Wall Street or tax policy, except to say, “I fall in a very pragmatic way.”

It’s that sort of talk that has raised alarm bells about Booker. Some former employees describe him as an insincere opportunist who uses Newark as a springboard and spends his free time schmoozing on New York’s moneyed East Side. Even some of his most influential financial backers wonder if he is more deeply committed to a set of values or his own advancement. In recent weeks, many liberals have expressed skepticism about Booker, who appalled them in May 2012, when, on “Meet the Press,” he called the Obama campaign’s attacks on private equity “nauseating.”

“That critique does not hold up to a magnifying glass at all,” says Booker, who, for starters, notes that he did pretty well in the recent Democratic primary. “All I know is, many of these bloggers wouldn’t walk down a street in my city without feeling insecure.” Booker argues that his connections to Wall Street helped fund Newark parks, that his Silicon Valley connections helped bring $100 million of Facebook founder and chief executive Mark Zuckerberg’s money in for Newark schools. But the liberal point of attack is not Booker’s only vulnerability. Skeptics look at his life story — suburbs, Stanford/Oxford Rhodes scholar/Yale Law, followed by his choice to live in crime-ridden housing projects and to conduct hunger strikes on drug corners — and see a made-for-TV candidate with an eye on the Oval Office. (If this was a stunt, it was an especially enduring one, lasting 15 years.)

“That’s really a phenomenon of the last two years,” Booker acknowledges, “when people started projecting me, not as this guy working in the inner city, but maybe as somebody who was going somewhere.” He adds, “I was saying this to a friend the other day, ‘If I were thinking my whole career about being a United States senator, I could name quickly to you a dozen things I would have never ever done.’”

Such as?

“He’s been dealing with one of them,” Booker says, pointing to the press secretary seated with him during the interview. “With Waywire.”

Waywire is the small video aggregation start-up founded by Booker with the help of gold-
plated investors such as Google Chairman Eric Schmidt and LinkedIn’s founders. In July, Booker amended his Senate campaign financial disclosure form to include his stake in the company, worth $1 million to $5 million. In August, the New York Times reported that the company had recently shuttered office space, laid off staffers and counted CNN President Jeff Zucker’s 15-year-old son, Andrew (“the young genius,” Booker calls him), as a board member. Booker insists there is nothing inappropriate about pursuing entrepreneurial interests while serving as mayor.

“I mean, there is a mayor across the river who has one of the largest media companies that’s named after him, for crying out loud,” Booker says, referring to New York mayor and media mogul Michael R. Bloomberg (I). Asked if he consulted Bloomberg, a mentor, about the Waywire deal, he says “I talked — I — I — I — I, no comment. He’s a dear friend! He’s a dear friend, we talk about a lot of things.”

Booker says that his involvement in Waywire is in part a result of his restless mind but also his lack of familial obligations. It is to his “great dismay” that “I have not settled down with a life partner.” He tells a story about how, early in his tenure as mayor, as murders continued to mount, he ran bawling past the places where Newarkers had been shot. He called a pastor friend and told him how broken he felt. At the end of the conversation, Booker expected some spiritual advice.

“You need to get married,” the pastor said.

After that, Booker says, he started dating more — although, he clarifies, not with Arianna Huffington, with whom he was rumored to have been involved. But he has kept that part of his life private because he says he needs some sacred spaces.

“Because how unfair is it to a young lady to put them in the spotlight if they haven’t signed up for that yet?” he says. “And people who think I’m gay, some part of me thinks it’s wonderful. Because I want to challenge people on their homophobia. I love seeing on Twitter when someone says I’m gay, and I say, ‘So what does it matter if I am? So be it. I hope you are not voting for me because you are making the presumption that I’m straight.’ ”

In a recent chat, Sen. Charles E. Schumer (D-N.Y), the veteran master D.C. operator, told Booker he had a hole in his heart that he didn’t even realize. “I said, ‘What do you mean, senator?’ . . . And he said, ‘You don’t have children.’ ” Informed that Schumer said exactly the same thing to this reporter years ago, Booker, no slouch at working people, looks genuinely crestfallen. “I thought that was just for me. It caught me completely off guard,” he says. “I don’t believe it’s just a line — like in ‘This Town.’  ”