Kadima, which has been slipping slowly in the polls, may drop a bit more before Israel’s March 28 elections, but it is still sure to win them handily. What will the government formed by it under the prime-ministership of Ehud Olmert look like?

It will of course have to be a coalition government. In Israel’s history, no single party has ever won the 61 seats needed for a majority in the 120-seat Knesset, and Kadima, with 37 seats in the latest surveys, is far from this.

One can predict at once who will not be in this coalition. Kadima, though self-declaredly centrist, is essentially a one-issue party, established by Ariel Sharon, and continued by his successors, as a vehicle for promoting a unilateral Israeli withdrawal from most of the West Bank, to borders of Israel’s choosing, on the model of last summer’s disengagement from the Gaza Strip. This immediately excludes the Likud, now controlled by the anti-disengagement rebels who caused Mr. Sharon to bolt the party before his incapacitating stroke, with a projected 14 seats in the next Knesset. It also rules out the joint list, currently given eight seats, of the right-wing National Religious and National Unity parties, which are closely aligned with the settler movement.

To this must be added Israel’s three Arab parties, now likely to win eight seats, too. Apart from the fact that all three oppose unilateralism on principle as a pre-emption of negotiations with the Palestinians, their fundamental hostility to the idea of a Jewish state has kept them out of all Israeli governments in the past and will go on doing so in the future.

Kadima’s most obvious coalition partners are on the left, in the Labor Party, given 20 seats by the polls, and the smaller Meretz, given six. Although both Labor and Meretz are still officially in favor of a negotiated resolution to the Israeli-Palestinian conflict, both also know that few of their voters still believe in this as a practical alternative, especially after the Hamas victory in the Palestinian elections. This is why they have chosen to run their campaigns almost entirely on social and economic issues. If Kadima would be willing to accommodate them on these issues, they would be ready to back it on unilateral withdrawal in return.

A Kadima-Labor-Meretz coalition comprising a 63-seat Knesset majority is thus a theoretical possibility. In it, Labor would be given the ministry of finance, which along with defense and foreign affairs is considered to be one of the three major cabinet portfolios, in return for supporting Kadima’s stand vis-a-vis the Palestinians. This would lead on the economic front to a strengthening of welfare programs and a halt in planned tax cuts at the expense of the economic liberalization program of former finance minister Benjamin Netanyahu – a step that Mr. Olmert and his associates, however unhappy about it they might be, would accept as the price of pushing unilateralism forward.

In reality, however, a majority based on 63 Knesset seats is not going to be enough for Mr. Olmert. A savvy politician, he has undoubtedly learned the lesson of Yitzhak Rabin’s having had a similarly small Knesset majority when he signed the Oslo Agreement in 1993. The result of this was that Israel, which had already been severely polarized between left and right, was split politically into two bitterly warring halves that nearly tore the country apart – a process that culminated in Rabin’s 1995 assassination.

The moral is clear: An Israeli prime minister must not lead his country into controversially fateful moves, especially ones involving major territorial concessions, without enjoying the broad backing of far more than half the population. This is precisely what Menachem Begin managed to do when he successfully negotiated peace with Egypt in 1979 at the cost of a painful withdrawal from Sinai.

Mr. Olmert will therefore seek to broaden his coalition by also bringing into it the more territorially moderate religious parties, such as the Sephardic Shas, with a projected 11 seats, and the ultra-Orthodox Yahadut ha-Torah, with six more. He may even seek to include in it the Yisra’el Beiteynu or “Israel Is Our Home” Party, a right-wing group running strongly at a projected ten seats and led by the former Netanyahu associate Avigdor Liberman. Once an ideological hard-liner on territorial issues, Mr. Liberman has recently been showing signs of greater pragmatism.

Together with the Hamas victory, this explains why Mr. Olmert has begun to define unilateralism in more territorially extensive terms so to include such areas as Hebron and the Jordan Valley that were not previously assumed to be a planned part of Israel in unilateralist doctrine. Hebron, with its great religious significance for Jewish tradition because of its hallowed Cave of the Patriarchs, will make it easier for Mr. Olmert to appeal to Shas and Yahadut ha-Torah; the Jordan Valley will register with the more security-minded Yisra’el Beiteynu. Mr. Olmert will also have to promise the religious factions to maintain the state-synagogue status quo and to continue funding a wide range of religious institutions – something that will be much easier for him to do now that the anti-clerical but otherwise politically centrist Shinui has collapsed with Kadima’s ascendancy.

All this could result in a Kadima-led coalition of 80 to 90 Knesset members. With such a majority behind him, Mr. Olmert could take Israel down the highly promising but also peril-fraught path of a West Bank disengagement without risking more civil discord than he and the country can safely handle. Any other fundamental changes in Israeli society that he might like to make will have to wait for another government.

Mr. Halkin is a contributing editor of The New York Sun.