In his first speech to supporters after Tuesday's national elections in Israel, the winner declared that there was "only one option" — a national unity government.

Normally that would be a strange thing for a winner to trumpet; national unity governments are what you get when there is no real winner and the largest parties are so weakened that they must band together against the extremes to avert total chaos. And that, in fact, is the situation after Israel's most recent election. Based on the exit polls, it appears that Prime Minister Benjamin Netanyahu's ruling right-wing Likud Party, and the centrist opposition Blue and White party headed by Benny Gantz, have almost equal representation at about half the seats needed to form a government.

But neither Gantz nor Netanyahu made that victory speech, because neither was the true winner of the election. The winner and speech-giver was Avigdor Lieberman, leader of the small (but not quite as small as it was) right-wing secular party, Yisrael Beiteinu ("Israel Our Home"). While Lieberman has long been viewed as both an extremist and a sower of chaos, for now he holds the balance of power in the Knesset. And if you want to know where Israel is likely going from here, he's a better guide than any other Israeli political leader.

Lieberman forced Israel's electoral "do-over" in the first place by refusing to join Netanyahu's government after last April's election, thereby depriving it of a majority. The dispute was over the drafting of yeshivah students, which the ultra-Orthodox parties opposed. But Lieberman had sat with those parties before, their disagreement over that issue and others notwithstanding. He seized on the draft question at this juncture not only because it was popular, but because he saw an opportunity to dislodge Netanyahu, enhance his own stature, and make himself indispensable to the next coalition.

That mission is now accomplished. After their losses, neither Blue and White nor Likud can form a plausible coalition. Likud's natural right-wing partners, the ultra-Orthodox and settler-oriented parties, look to have gained seats, but not as many as Likud lost. Without Lieberman, there will not be a right-wing government. But Blue and White has even fewer natural partners. The Zionist parties to their left — Labor and Democratic Union — will have at most a dozen seats between them, leaving them well shy of the 61 needed to form a government.

And while the two major parties could join forces, their majority together would likely be so thin that only a handful of defections would topple the government. To ensure against that eventuality, they need another coalition partner — and Lieberman poses the fewest ideological obstacles while also bringing the most seats to the table.

While Lieberman poses the fewest obstacles, that doesn't mean his perspective isn't ideologically distinctive — and disturbing. Lieberman is an unapologetic ethno-nationalist. He has proposed revoking the citizenship of Arab Israelis who refuse to take an oath of loyalty to the Jewish state, and transferring populous Arab areas within Israel to the Palestinian Authority in exchange for Jewish settlement blocs on the West Bank.

Though he lives in a West Bank settlement, he has also voiced support for a viable Palestinian state, and affirmed that he would evacuate his own home in the context of a peace deal. And his approach to religious questions is far more nuanced than his recent stand on principle would suggest.

Lieberman is a fairly rare political animal: a pragmatic extremist. And the main obstacle to his continued rise is the degree to which he is loathed by enemies and allies alike. In these ways, Lieberman may be the true heir to former Israeli Prime Minister Ariel Sharon: a man of unequivocally right-wing instincts, willing to be brutal, to take big risks and loud stands, but lacking the particular ideological hangups of those raised in Revisionist Zionist or Religious Zionist traditions.

If Lieberman has now made himself the indispensable match-maker to a national unity government of Likud and Blue and White, he will likely prove a dangerous addition to the coalition, ready to tear it apart whenever he sees an advantage in standing on principle to do so — as he did to Netanyahu in 1997, to Sharon in 2004, and to Ehud Olmert in 2008. But for now, they have few if any other choices.

The man with the greatest potential to change that calculus is the other winner of the election: Ayman Odeh, head of the Arab-dominated Joint List, now the third largest grouping in the Knesset. If Odeh actually brought his party and its allies to consider joining a Zionist-led government, it could radically change the possibilities for Israeli politics. But that is a bridge neither side can seriously contemplate crossing. So the larger the Arab bloc grows, the more difficult it is for any coalition of Zionist parties to form a majority, and the more power an independent player like Lieberman has to dictate terms.

So Lieberman remains the man of the hour. Does his idiosyncratic perspective truly represent the emerging Israeli center? Or will he be consigned to the periphery once more?

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