Politicians typically lose power as their days in office wind down. Mayor Bloomberg could be the first mayor whose power will grow as his time in City Hall nears conclusion.

This has nothing to do with his lack of interest in future political office. And this has nothing to do with the fact that special interests didn’t fund his campaign. Mr. Bloomberg’s wealth is the insurance policy against becoming a lame duck.

Every day that that passes brings Mr. Bloomberg one day closer to shedding his fortune (at least $5 billion according to Forbes, although some insiders say almost triple that) on causes he deems worthy. With that kind of cash on the horizon, potential adversaries – especially those who run cultural groups or other non-profits – will be reluctant to block Mr. Bloomberg’s initiatives.

This was true to some extent during his first term, and then became crystal clear during the election as potential supporters of Mr. Bloomberg’s Democratic opponents worried they would be punished. This punishment can extend well beyond Mr. Bloomberg’s mayoral powers, given that he already gives away well over $100 million annually. That’s chump change compared to the tsunami of cash Mr. Bloomberg has vowed to let loose when his political foray ends.

During his first term, Mr. Bloomberg’s most vocal – and successful – adversary was Cablevision, the Long Island-based cable television company that owns Madison Square Garden. Cablevision spent millions of dollars to block Mr. Bloomberg’s dream for a West Side Stadium a few blocks from the Garden.

At first glance, Cablevision appeared to have nothing to lose in the fight and everything to gain. The company owns Manhattan’s marquee indoor venues, the Garden and Radio City Music Hall, and quite understandably was worried about a state-of-the-start enclosed stadium competing for events just a few blocks away.

But Cablevision could soon find out that the first glance isn’t the only view. Mr. Bloomberg has plenty of power to exact revenge – the only question now is whether he will use it. City Hall insiders say time will tell.

Cablevision is exploring whether to move Madison Square Garden across 8th Avenue to the Farley Post Office, only a portion of which is being converted into the new Moynihan Station. Also, the company’s lucrative cable television franchise dominating the Bronx and Brooklyn is up for renewal in a year. Both issues require the city’s cooperation.

Complicating the situation is how Mr. Bloomberg is reshuffling responsibilities among his second-term deputy mayors, with Daniel Doctoroff, who oversees economic development, taking on broader roles. Among other agencies that are being added to his portfolio, Mr. Doctoroff will supervise the department of buildings and the department of information technology.

Mr. Doctoroff originally convinced the mayor to support a West Side Stadium as the centerpiece of New York City’s bid for the 2012 Summer Olympics. Even with the stadium, New York would have been an extra-long longshot for the Games. But Mr. Doctoroff, who singlehandedly launched the city’s Olympics efforts, will surely never forgive Cablevision for the lobbying and public relations campaign that blocked the stadium and thus guaranteed the Olympics would go elsewhere.

And now Mr. Doctoroff is directly in charge of agencies that will help determine Cablevision’s success. Converting the post office into a sports arena would require a series of waivers, permits and permissions from the buildings department. Renegotiating the cable franchise will require help from the department of information technology, just as phone companies like Verizon are salivating at the chance to enter the cable market.

The irony is thick: The company that dealt Mr. Bloomberg his biggest political blow is about to ask the City Hall aide most personally humiliated by that blow for a series of favors.

Although Mr. Bloomberg and Mr. Doctoroff could forgo the chance for revenge, Cablevision’s experience is a cautionary tale for those who do battle with City Hall. Months before the stadium fight began dominating the headlines, Mr. Bloomberg vented his anger at the Dolan family that runs Cablevision when he disclosed a private phone call from James Dolan complaining the stadium would hurt the Garden. After marching in a summertime parade, Mr. Bloomberg mentioned to a Newsday reporter: “The biggest guys that are making a fuss here are, plain and simple, the Dolans.”

At the time, business leaders were privately aghast at the mayor’s loose lips. Mr. Dolan was hardly the first mogul to register a concern with City Hall, and others wondered if their mayoral conversations would also wind up in the newspapers. Mr. Bloomberg didn’t call a press conference to announce his anger, and he didn’t ask an aide to leak his opinions anonymously.

From that day forward, Mr. Bloomberg’s pique at the Dolans would only grow. And business titans who do business here heard the message loud and clear that tangling with City Hall has very public consequences. The Dolans could be among the first to understand the power that Mr. Bloomberg can harness in the coming years.

Yesterday Mr. Bloomberg finished finessing his inner circle for the next four years, rewarding aides who’ve worked for his campaign and administration while shunning outsiders who might bring fresh perspective. Freedom from future political or financial considerations frees Mr. Bloomberg to surround himself with people he wants, rather than people others want or people he might need down political road.

The mayor can pursue policies he likes without worrying about his financial prospects after he leaves office. In a unique twist, he’ll have even more influence in a certain sense when he is no longer mayor and starts giving his money away. In the meantime, the specter of that cash flowing means Mr. Bloomberg will probably never really be a lame duck.

Mr. Goldin’s political column appears weekly.