David Dinkins sat at a table, his hands resting on his cane. The party, a recent awards gala in lower Manhattan, bustled around him, but he was still. He didn’t need to move. A steady stream of well-wishers approached, coddled and thanked the 90-year-old former mayor of New York City.

“Hi Mayor, how are you?”

“Mr. Mayor, how are you doing?”

Does he ever get tired of it?

“If you like people, and you like public service,” he said, “there’s no job better than being mayor of New York.”

It’s a belief that many people-loving public servants share, and with the 2021 New York City mayoral race just three and a half years away, a few of them have set their sights on City Hall and are already prepping for mayoral bids.

“If you’re a public official and haven’t already started organizing and fundraising toward 2021, you’re not serious,” said Mark Green, the 2001 Democratic nominee for mayor.

“It really takes at least four years. It takes someone either who had thought of running four years before – or ideally, in utero – to put everything in place to have a record, resources, recognition to be treated seriously,” Green said.

In interviews with more than a dozen political insiders, including representatives for all the rumored candidates, four Democrats came up as the main contenders: New York City Comptroller Scott Stringer, New York City Public Advocate Letitia James, Bronx Borough President Rubén Díaz Jr. and Brooklyn Borough President Eric Adams.

In different ways, the four have made clear their interest in the position. Adams was the most explicit, sharing a statement with City & State about his love for serving the city. “Throughout the years I have continuously stated that I’d be privileged to bring that service to City Hall as mayor,” he said. “While some may have played coy about their ambitions, I’ve been upfront for a long time. I believe that’s what New Yorkers respect and deserve.”

Similarly, Díaz told NY1 Noticias in January that he’s interested in running for mayor in 2021, when he’s term-limited out of his position. He opened a campaign account, and the Bronx booster has been traveling far afield of his home borough in recent months, building relationships in midtown Manhattan, Midwood and Bushwick in Brooklyn as well as Ridgewood and Far Rockaway in Queens.

Neither James nor Stringer would openly admit to their interest in running for mayor, but their dueling 2018 inauguration speeches did not go unnoticed. Both have already opened 2021 campaign accounts, and Stringer has transferred in $1.3 million from his 2017 account as a show of force – far outpacing Diaz’s $436,000, Adams’ $309,000 and especially James’ $31,000.

Those bottom lines will be the numbers to watch over the next three and a half years. All four of the major names are term-limited at the end of 2021, and New York City Mayor Bill de Blasio will have to leave office as well. That will likely set up another race like 2013, when a handful of prominent candidates battled for the open seat.

“I think if candidates are smart, all they’re trying to do is raise money,” said Keith Wright, the chairman of the Manhattan Democratic Party and a former assemblyman. “It’s going to cost a lot of money. Whatever the mayor’s race cost five years ago, it’s going to cost a lot more this time around.”

Stringer, James, Díaz and Adams already have a leg up, with the chance to soak up “the vast majority of the money,” said Doug Muzzio, professor at Baruch College’s Marxe School of Public and International Affairs. “If the big four raise enough money and they suck the energy out of the news coverage, it’s going to be tough for a noncitywide or boroughwide candidate to run.”

But that isn’t stopping others from trying. Queens Borough President Melinda Katz has opened a 2021 campaign committee, and she held her first fundraiser in Manhattan on Feb. 12.

Katz ran for city comptroller in 2009, losing in the Democratic primary to John Liu, but she told City & State she may aim higher this time. “I think clearly you look at mayor first,” she said. “So we are gauging interest out there. … Four years is a long time, but it’s really tomorrow.”

Other prominent politicians may be eyeing bids as well. Like Adams, Díaz, James and Stringer, Rep. Hakeem Jeffries considered challenging de Blasio last year. But after federal and state prosecutors declined to charge de Blasio in a probe over his campaign fundraising, the mayor’s re-election seemed inevitable, and Jeffries declined to run. Though Jeffries worked behind the scenes to influence the 2017 New York City Council speaker’s race, a number of political observers think that Jeffries’ future is in Washington, where he serves on the House Democratic leadership team.

Jeffries said he’s focused now on winning a Democratic majority in both houses of Congress in November. “After that, we can take a closer look at where the opportunities to serve our country may be moving forward. But there will be enough time for that to happen prior to 2021,” he said. “With respect to the mayor’s race, nothing has been ruled in, nothing has been ruled out.”

Corey Johnson’s recent election as New York City Council speaker has inevitably added his name to the 2021 conversation. Johnson will be term-limited in 2021, and three of the four previous speakers – Peter Vallone Sr., Gifford Miller and Christine Quinn – launched mayoral bids after leaving the council. Johnson could not be reached for comment, but his answer on whether he would run for mayor seemed to evolve after just three weeks on the job. On Jan. 2, he was a hard “no.” On Jan. 22, he said, “You can never say never.”

Still other names have been thrown in the mix. Success Academy Charter Schools founder and former New York City Councilwoman Eva Moskowitz has long been considered a possible contender. The Wall Street Journal reported in November that New York City Deputy Mayor for Housing and Economic Development Alicia Glen may be considering a run as well as Shaun Donovan, former budget director under President Barack Obama, who previously served in New York City Mayor Michael Bloomberg’s administration. None of them could be reached for comment.

Former Deputy Mayor for Economic Development Dan Doctoroff, another Bloomberg-era appointee, also came up repeatedly as a possible candidate. Doctoroff is currently chairman and CEO of Sidewalk Labs, a subsidiary of tech giant Alphabet. Sidewalk Labs spokesman Dan Levitan directed City & State to an October interview in which Doctoroff said working for Bloomberg was a singular experience and that he doesn’t think running for office is in his future.

The ghost of Bloomberg looms over every election now, since there is always a chance that a candidate with money could mount an outsider run. Real estate executive Paul Massey Jr. tried last year, but ended his campaign well before the Republican primary. Billionaire businessman John Catsimatidis put millions of dollars into his 2013 campaign, but lost in the Republican primary to Joe Lhota, a former deputy mayor in Rudy Giuliani’s administration. Both Massey and Catsimatidis are considered possible challengers for the Republican line in 2021, as is New York City Councilman Eric Ulrich, who considered a run last year and will be term-limited out of office in 2021. Assemblywoman Nicole Malliotakis, the 2017 Republican nominee for mayor, is also considering another run. But the Republican primary is seen as an afterthought in a city with a more than 6-to-1 Democratic voter registration advantage.

“It doesn’t matter,” said Muzzio of the potential Republican contenders. “They’re going to lose. You can forget it.”

One issue nobody will be forgetting is the race and gender politics at play. James and Katz could compete to become the city’s first female mayor. Díaz, whose father grew up in Puerto Rico, could be the first Latino mayor. Adams, James and Jeffries all hail from Central Brooklyn and each could be the city’s second black mayor after Dinkins.

But don’t expect to hear much of this for the next couple years, unless you’re a political power player or a big-time donor.

“This is the courting and sparking stage, if you will,” Wright said. “This is now 2018 and anybody that’s running for citywide office, this is the planting of the seed time.”