his is a city in which it is tough to stay oriented, and that is especially true with politics, which is emerging with a vengeance from its post-Sept. 11 hiatus.

Through most of this odd and ultimately tragic election season there appeared to be one constant. Among Democratic primary candidates, Public Advocate Mark Green held the lead in nearly all of the opinion polls. But on Tuesday night, when the hard votes were counted, that lead had evaporated.

Mr. Green finished behind the Bronx borough president, Fernando Ferrer, whose candidacy ・at least in the early stages ・was only lightly regarded by a wide range of politicians and pundits.

The two men will face each other in a runoff on Oct. 11. Between now and then, the strength of character and sense of unity that has been so evident in the city since the trade center tragedy will undergo a severe test.

There is every chance the runoff will be ethnically charged. Mr. Ferrer finished first in Tuesday's election, but his support came overwhelmingly from Latino and black voters. One of the knocks on the borough president was that his campaign's emphasis on fighting for "the other New York" ・which Mr. Ferrer defined as those who did not do well during the Giuliani years ・was divisive.

To win, Mr. Ferrer will have the difficult task of rounding up at least some white voters ・many of them moderate to conservative ・who presumably pulled the lever on Tuesday for the City Council speaker, Peter Vallone, or Comptroller Alan Hevesi.

Mr. Vallone endorsed Mr. Ferrer yesterday, but how many of his votes he can deliver to the borough president remains to be seen. Former Mayor Ed Koch, who had endorsed Mr. Vallone in the primary, raised one of the potential stumbling blocks yesterday.

Mr. Koch said he did not believe Mr. Ferrer could have reached the runoff without the strong support of the Rev. Al Sharpton, and that Mr. Sharpton was entitled to claim a certain amount of the "spoils" of a Ferrer administration.

Mr. Koch said he had been happy to work with Mr. Sharpton on some issues, "when it was appropriate," but added, "I certainly wouldn't want him to have the right of a veto of the police commissioner, which I'm certain he will have."

(The Ferrer campaign denied that Mr. Sharpton would have veto power over any commissioner, and Mr. Sharpton said he would spend most of the time between now and the runoff campaigning for Mr. Ferrer in black and Latino neighborhoods.)

Mr. Green would likely have an easier time pulling votes from the Vallone and Hevesi constituencies. But he would have to go after those votes carefully, making sure that he is not seen as encouraging a backlash that would jeopardize his own standing with black and Hispanic New Yorkers.

The land mines of ethnic politics are all over the place.

Mr. Green ・who was counting on a significantly stronger showing Tuesday ・may also have some image bolstering to do. He needs to convince voters across the board that he has the political strength and savvy to both win the tough elections and lead in tough times.

Meanwhile, Mayor Giuliani has done all he could to further muddy the electoral waters. Yesterday he said, "What I'd like to do is to maintain the unity that exists in the city."

But in a taped television interview last night the mayor made it clear that, despite the inconvenience of term limits, he was still seeking a way to stay in office beyond Dec. 31.

Asked if he was willing to stick around if the term-limits law could be circumvented, Mr. Giuliani ・who is riding a phenomenal wave of popularity ・said, "Yes, I couldn't walk away from it. . . . I would feel that I was walking out on my duties and obligations if I did."

So welcome to the strangest election season of all. The Democratic field, whittled to two, is completely overshadowed by a Republican who, by law, is not permitted to run.

If the law is changed ・an unsettling prospect for many ・new and bitter antagonisms will immediately arise.

Voters are uncertain, and many are frightened. And the unity fostered by tragedy is in danger of being fractured by the partisanship that inevitably accompanies politics.