A former Bronx Democratic Party boss, Roberto Ramirez, is sitting in the Grand Havana Room above Fifth Avenue chain-smoking Marlboros. He is the definition of dapper: Over yellow suspenders, he wears the kind of suit that makes you want to rub a lapel through thumb and forefinger, and he sports a fresh manicure.

The Havana Room, a club atop 666 Fifth Ave., is one of the few places in the city where smoking is still permitted. It was grandfathered in when Mayor Bloomberg’s smoking ban went into force because, some people say, it is Mayor Giuliani’s favorite place to enjoy a cigar. The rooms are dark and paneled, and it looks like the type of place where players gather.

In that respect, it is a perfect haunt for Mr. Ramirez, 55, one of the city’s consummate political players and, if the polls are to be believed, the man who will be the power behind the throne when the former Bronx borough president, Fernando Ferrer, wins City Hall next November.

“No one said I would be a kingmaker when I supported Chuck Schumer and delivered the entire Bronx delegation to him,” Mr. Ramirez said, lighting a cigarette. “Certainly no one said that when I supported Hillary Clinton and worked my heart out for her. I just finished running Jeff Klein’s race for Senate. Everyone said a Republican was going to win Guy Velella’s seat and Jeff won. But no one said if Klein wins, is Ramirez doing to be a power broker. So why do they say that I am a kingmaker with Fernando Ferrer?”

Messrs. Ferrer and Ramirez have been like brothers for more than a decade. The former Bronx party chief said he first met Mr. Ferrer in 1992, when the latter was a candidate for City Council hanging up campaign posters at Arthur Avenue. The meeting evolved into a political friendship when Mr. Ramirez signed on to help Mr. Ferrer in the race. The two have been close ever since.

It is that kinship that has some observers concerned. “If Freddie wins, then Ramirez will be running the city,” one political analyst, who declined to be further identified, said. “Ramirez will be the real power, the man behind the scenes. It will be a disaster.”

Others are quick to say such talk diminishes Mr. Ferrer, who is a political force in his own right. “They always say that the campaign guru holds the real power when someone is in office, and it is generally not true,” Mayor Koch told The New York Sun. “Roberto Ramirez will have great input and a close relationship with Freddie, no question about that. But Freddie isn’t a yes-man and people forget that.”

Rather than allow Mr. Ferrer to be interviewed for this article, press aides referred inquiries to his campaign finance chairman, Leo Hindery. Mr. Ramirez is expected to help the Ferrer campaign in mobilizing the Latino community, according to Mr. Hindery, who for a time was a contender to be the next Democratic national chairman.

“For the Latino community in New York, Roberto is the go-to guy,” Mr. Hindery told the Sun. “People have come to look to him as they look to characters like Karl Rove. Just like people say that Rove is the brains behind Bush, now people say Roberto is the kingmaker behind Ferrer. I don’t see it that way. Frankly, Freddie is just too capable and too smart for that.”

Messrs. Ferrer and Ramirez are part of a new generation of Puerto Rican politicians who started amassing their clout as neighborhood activists. In 1986, Mr. Ramirez ran for state Assembly against Gloria Davis. He lost, but garnered 42% of the vote. Four years later, backed by the Bronx machine, Mr. Ramirez landed in Albany. By 1994, he had left the state capital to become chairman of the Bronx Democratic Party, rebuilding it after the corruption scandals of the late 1980s. He stepped down in 2002 to open his own lobbying and political consulting firm, Mirram Group, which has a roster of varied clients including the developer of a new Target store and shopping mall on West 225th Street, trade groups in the health-care industry, Fox Television, the Yankees and the YES Network, the NYC2012 Olympics drive, and Meals on Wheels. Other clients have included Ms. Clinton, Eliot Spitzer, and the Transportation Workers Union.

Seeing Mr. Ramirez in the haze of smoke in the Grand Havana Room, talking about “taking advantage of” his “full citizenship” by helping the city’s Democrats win political office, underscores just how far he has come. He arrived America from Puerto Rico in 1969 at age 19, speaking barely a word of English. His first New York job was as a janitor in a building on the East Side. He later enrolled at Bronx Community College and eventually spent the 1980s going to law school at NYU.

If the story ended there, it would be remarkable enough. Instead, Mr. Ramirez went on to become what friends and foes alike say is one of the most effective political strategists in the city.

“He’s a very skilled practitioner,” a former mayoral candidate, Ruth Messenger, said. Mr. Ramirez is said to have delivered the Bronx in her failed race against Rudolph Giuliani in 1997.

“He could have played it safe and followed the crowd when it looked like I was going to lose,” Ms. Messenger said. “Instead, he did what a good county leader would do, he delivered. People notice things like that.”

Some Democrats grumble that Mr. Ramirez almost single-handedly presented the 2001 election to Mr. Bloomberg when he locked horns with Democratic nominee Mark Green. The story goes that Mr. Ramirez was upset by Mr. Green’s post-runoff comments and, in particular, his demonizing of Mr. Ferrer during the primary by linking him with the Rev. Al Sharpton in a “Can we afford to take a chance?” television campaign. Mr. Ramirez wanted the Green campaign to denounce the inflammatory comments. When they didn’t, Mr. Ramirez responded by keeping his troops home on Election Day.

Mr. Bloomberg wound up with 50% of the Hispanic vote – 11 points better than Mr. Giuliani ever did – and 22% of the black vote. Mr. Bloomberg also ended up with 38% of the union vote. While Mr. Ramirez is loath to take responsibility for Mr. Green’s loss, he does acknowledge he didn’t work for the candidate after the runoff. “I did not go out there the way I always do and work for Mr. Green,” Mr. Ramirez said in an interview. “I wasn’t responsible for his loss. I was responsible for standing up for what I believe.”

That, political analysts said, is Mr. Ramirez’s strength, and what he can provide for the Ferrer mayoral campaign is an uncanny ability to build coalitions and get the vote out. The concern bubbling below the surface, however, is that Mr. Ramirez will use racial politics to do so.

“Ramirez doesn’t hesitate to play the race card,” one political observer, who declined to be further identified, told the Sun. “He used race to his advantage in the Engel-Seabrook congressional race in 2000, and I predict we’ll see that again next year, too.”

In 2000, a black state senator, Larry Seabrook, ran against Eliot Engel, an Anglo, six-term congressional incumbent from Riverdale. Mr. Ramirez, who had previously supported Mr. Engel, backed Mr. Seabrook instead. Accusations flew, and Mr. Engel claimed the Bronx party chief was using race to defeat him in a district that has a black and Latin majority. His proof: The Seabrook campaign printed buttons urging people to elect the county’s first African-American congressman. Mass mailings went out that read, “It’s time for us to be represented by one of us.”

Mr. Ramirez said that it was Mr. Engel who played on race, because he was telling anyone who would listen that the only reason the party chief didn’t back him was that he wasn’t black. “I didn’t back him because he wasn’t the best candidate for the job,” Mr. Ramirez told the Sun. “He had been there long enough.”

Whatever Mr. Ramirez’s motivation for supporting Mr. Seabrook – some say he backed the black candidate as a way to win the Rev. Sharpton’s support for Mr. Ferrer in the 2001 mayoral campaign – the upshot was that the Bronx party boss emerged from the race with a taint of anti-Semitism. Others who were privy to the episode, such as Mr. Koch, said it was a misunderstanding that has become part of the city’s political lore.

“My involvement with him would never exist if I thought he was anti-Semitic,” Mr. Koch told the Sun. “I remember the incident. When the Jewish community in Riverdale complained about his support of Seabrook, his response was, ‘But look at all the Jews I have supported.’ He had supported Engel in the past but switched to Seabrook. Frankly, I thought it was a bad rap to accuse him of anti-Semitism. That wasn’t what it was.”

That would all be water under the bridge were Mr. Ramirez not a dominant figure in Mr. Ferrer’s latest bid for mayor. While Mr. Ramirez said unequivocally that he would not seek a job in a Ferrer administration, his detractors worry about how much sway he would hold if his old friend becomes mayor.

Mr. Ramirez said he has an eye on running state and national campaigns. He will be working with Mr. Spitzer in his race for governor, he said, and would like to work on a presidential election in 2008, either for Ms. Clinton or perhaps for the governor of New Mexico, Bill Richardson.

“Most people run campaigns as a science. I think campaigns are a science and an art,” he said, exhaling and adding to the smoke in the air above Fifth Avenue. “I ache for the opportunity to go from New Hampshire to California. That is where I am headed. People who say I am some sort of power behind Freddie don’t understand me and don’t understand that he dances to his own tune. People may not fully recognize the strength and clarity of his purpose. When he makes decisions, ain’t nobody going to change them.”