Foreign minister Avigdor Lieberman was once so close to Israeli prime minister Benjamin Netanyahu that the two political leaders joined forces to fight the 2013 elections on a joint ticket. When Lieberman stepped down as foreign minister in 2012 pending resolution of charges of fraud and breach of public trust, Netanyahu held the foreign affairs portfolio himself, with every intention of re-appointing Lieberman to the position when Lieberman was subsequently cleared of the corruption-related charges.

That makes it all the more spectacular that Lieberman announced Monday that he was resigning his office and that his party, the secular nationalist Yisrael Beiteinu (ישראל ביתנו‎, ‘Israel is Our Home’), would not be joining Netanyahu’s next governing coalition, throwing the prime minister’s plans for a third consecutive term into disarray.

With 48 hours to go before Netanyahu has to assemble a government, he now has to deal with the loss of six seats that have reduced his expected coalition to a bare majority of 61 of the Knesset’s 120 seats — not to mention a sudden fight to replace Lieberman as foreign minister. Netanyahu’s decision, rushed though it may be, will set the tone for Israel’s troubled relations with the United States and with Europe. Moreover, without Yisrael Beitenu, Netanyahu’s government could collapse on the whim of a single MK, including hard-line allies on the Israeli right.

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That’s renewed the growing speculation that Netanyahu might be forced, either now or in coming months, to seek a national unity government with the largest opposition party, the Zionist Union (המחנה הציוני‎), a coalition between the center-left Labor Party (מפלגת העבודה הישראלית) and a bloc of moderates led by former justice minister Tzipi Livni. The Zionist Union’s leader Isaac Herzog reiterated his refusal, however, to join a Netanyahu coalition. Though Netanyahu won a two-week extension to form a government from Israeli president Reuven Rivlin in late April, Herzog will likely have his chance to form a government if Netanyahu fails to do so before the May 7 deadline.

Lieberman, for what it’s worth, blamed Netanyahu’s concessions to the haredi parties that seek the repeal of laws passed by secular lawmakers in the prior government to reduce military exemptions for ultraorthodox students and liberalize marriage laws, which made official Jewish weddings much easier for Russian immigrants who vote for Yisrael Beitenu. Lieberman also challenged Netanyahu’s toughness on Gaza, and he bemoaned the way that Netanyahu and allies abandoned a controversial bill to proclaim Israel a ‘Jewish state.’ Many commentators in Israel were quick to ascribe more cynical motives to Lieberman, who had once harbored dreams of succeeding Netanyahu as prime minister, and Likud officials vented their fury with Lieberman.

Yisrael Beitenu’s six seats will deprive Netanyahu of the wider majority he hoped to assemble through a six-party coalition that was always assumed would also include:

• Netanyahu’s own center-right Likud (הַלִּכּוּד‎), which won the country’s March 17 election to take 30 of the Knesset’s 120 seats;

• Kulanu (כולנו‎, ‘All of Us’), with 10 seats, the newly-formed party of former Likud communications minister Moshe Kahlon, who has been promised the finance ministry and a handful of other posts central to Kahlon’s goal to reduce the cost of living and rising economic inequality in Israeli society;

• Shas (ש״ס‎). with seven seats, is once again under the leadership of the relatively dovish Aryeh Dery, who spent nearly a decade and a half out of politics due to a bribery conviction. Shas signed a deal with Netanyahu late Monday to join the coalition, and it will hold, among others, the economy and religious affairs ministries, with a pledge to roll back laws from the last government that reduce exemptions for yeshiva students to serve in the Israeli Defense Forces;

• United Torah Judaism (UTJ, יַהֲדוּת הַתּוֹרָה הַמְאוּחֶדֶת), another haredi party that appeals to the ultraorthodox voters of Ashkenazi descent, has six seats; and

• Bayit Yehudi (הבית היהודי, ‘The Jewish Home’), with eight seats, reduced in large part because Netanyahu veered so far to the right during the election campaign in a bid to win right-wing support. Its leader, Naftali Bennett, a former chief of staff to Netanyahu, has emerged at times as a sharp critic to Netanyahu as economy minister from 2013 to 2015, most especially on Netanyahu’s right flank on everything from settlements to Gaza.

Bennett and the Jewish Home now have all the leverage in coalition negotiations. Though Bennett is said to have settled on heading the education ministry, he will almost certainly make a new claim on the foreign ministry with Lieberman’s resignation. But if Netanyahu decides he must turn to a national unity coalition in the coming months, he would almost certainly yank Bennett out of the foreign ministry in favor of Herzog.

Appointing Bennett to the foreign ministry would also alarm U.S. and European allies, who hardly see the hard-liner as a voice of peace and negotiation. But Bennett now holds Netanyahu’s hopes in his hands — if Bennett decides the prizes of coalition aren’t grand enough, Herzog would get his chance to form a government. If Herzog, as expected, fails at forming his own majority, Israel would hold new elections.

Netanyahu, who has committed to retaining the popular (and loyal) Moshe Ya’alon, a Likudnik, as defense minister, must prefer handing the foreign ministry to another member of Likud, including popular interior minister and rising star Gilad Erdan or the Tunisia-born former foreign minister Silvan Shalom. But faced with the choice of losing power, Netanyahu may well find he has to deliver the foreign ministry to Bennett instead, giving an international profile to one of his canniest conservative rivals.