Congressional vacancies in Manhattan are rarer than cheap apartments in the Big Apple.

So it’s hardly surprising that a long line of candidates is forming in New York’s 14th district as nine-term Rep. Carolyn Maloney (D) inches closer to running for Senate next year.

The district, which covers most of Manhattan’s East Side along with some neighborhoods just across the East River in Queens, has several young, accomplished officeholders who are itching to move up the political ladder. But it’s also one of the wealthiest and most educated Congressional districts in the

country, and there’s no shortage of business leaders, celebrities and civic do-gooders who view Maloney’s seat as a political launching pad. One name being mentioned as a possible candidate: Karenna Gore Schiff (D), a lawyer and author who is the oldest daughter of former Vice President Al Gore.

“That’s a neighborhood with a lot of very fine candidates,— said Joseph Mercurio, a Manhattan-based political consultant who works for Democrats and Republicans. “I think it would be a very spirited campaign, with a lot of issue conversation and a lot of [voting] record conversation.—

As recently as a decade ago, liberal Republicans were still winning political office on the East Side — and Maloney, in fact, ousted one of them, then-Rep. Bill Green, back in 1992. But thanks in part to Maloney’s political operation, GOP officeholders have become extinct on the East Side — meaning the Democratic primary is likely to be the ballgame if there is a race to replace Maloney in the House. Greg Camp, a lawyer whose wife heads the local National Organization for Women chapter and who lost a special state Assembly election a few years ago, is considering the race on the Republican side.

There is no way to minimize what a big deal it would be if the Maloney were to run for Senate: Excluding special elections, there has been no open-seat House race in Manhattan since 1976, meaning the stakes — and the cost — of such a race would be extremely high.

“This is the source for more fundraising than any other Congressional district in America, in both parties,— said Evan Stavisky, a New York Democratic consultant and lobbyist. “I would assume on the candidate side that it would shatter all spending records for a Congressional race.—

Several of the possible candidates have close ties to Maloney — and to each other. One exception — yet one of the strongest potential contenders, inasmuch as her district has significant overlap with the 14th Congressional district — is state Sen. Liz Krueger (D). Krueger, 51, one of the oldest possible candidates, has suggested that she is ready to become a candidate for Congress if Maloney moves on, in part because she is eager to escape the political dysfunction gripping Albany.

There is some question among New York insiders whether Krueger, whose father was a wealthy Lehman Brothers executive, would be able to partly self-fund a campaign; many believe the family has absorbed enormous financial losses in the past year.

Also eyeing the race from the Upper East Side are two close friends and political allies, New York City Councilman Dan Garodnick (D) and state Assemblyman Jonathan Bing (D). Both are energetic, 30-something pols who are potent fundraisers; both are tight with Maloney, Bing especially. Few insiders can imagine the two running against each other.

City Councilwoman Jessica Lappin (D) is another East Side officeholder considering the race. She is a protégé of former City Council Speaker Gifford Miller (D), a former top Maloney staffer who was once thought to be a logical successor for the Congresswoman. But even though he is only in his early 40s, Miller, after an unsuccessful run for mayor in 2005, appears to be done with politics — at least for now.

About 30 percent the district’s population is in Queens, which suggests that Queens voters and officeholders could play a role in any race to succeed Maloney (meaning Maloney’s Congressional colleague, Rep. Joe Crowley, who doubles as the Queens Democratic boss, will be a key player). But the borough’s influence in the district is diminished when you talk about registered voters; it’s diminished even further when you talk about likely Democratic primary voters.

Still, some Queens pols are mentioned as potential Congressional candidates, led by Councilman Eric Gioia (D). Gioia is running a long-shot campaign for New York City public advocate — the No. 2 post in city government — this year. But even if he loses, the race is raising his profile around the city, and his wife is one of the top Democratic fundraisers in New York.

Another possibility is Councilman Peter Vallone Jr. (D). He is considerably to the right of most of the district’s voters, but his father is former Council Speaker Peter Vallone (D), who ran unsuccessfully for mayor and governor, and presumably has plenty of chits to call in.

Also mentioned is Assemblyman Michael Gianaris (D), a political reformer who has a strong fundraising base in the Greek-American community.

All three Queens officeholders who are mentioned as potential Congressional contenders are in their 30s.

No matter who runs, Maloney could have a tremendous influence on the outcome.

“Carolyn built the Democratic Party on the East Side of Manhattan, and she took this district from being marginal to being reliably Democratic,— Stavisky said. “Her support, whether explicit or tacit, is really going to be the key to a candidate’s success.—

Another powerbroker in the district is veteran state Assembly Speaker Sheldon Silver (D), who lives on the Lower East Side. He is known to be less fond of Krueger than some of the other potential candidates.

But the political calculations in the district could be scrambled if a multimillionaire or a political celebrity, like Gore Schiff, the former vice president’s 35-year-old daughter, decides to run. Democratic operatives in New York and Washington, D.C., said this week that Gore Schiff is openly discussing the possibility of running. She did not respond to a message left for her this week at the Association to Benefit Children, a New York nonprofit where she serves on the board of directors.

“It’s a super politically engaged and attuned district, and it’s an open-seat district,— one well-connected New York Democrat said. “The idea that a local assemblyman or state Senator would deter a celebrity candidate from running is laughable.—