The quick snapshot, taken on a parliamentary aide’s mobile phone, belies the drama behind an epochal moment in Israeli politics.

To the left, the former TV anchor Yair Lapid, 57, and leader of a centrist party that came second in Israel’s elections in March, perfectly coiffed despite weeks of frantic negotiations that he has spearheaded.

In the middle is Naftali Bennett, 49, an ultra nationalist rightwinger whose party has just six seats out of 120 in the Israeli parliament and who is poised to become prime minister.

And to the right the man analysts call the “star of the story”, 47-year-old Mansour Abbas, the leader of an Islamist party for Israel’s Muslim minority, a genial smile on his face as he prepares to make history. His Arab party is the first in Israeli history to join a Zionist government.

With his final signature on a coalition deal, the three men pushed prime minister Benjamin Netanyahu, the man who has towered over Israel and the Middle East for decades, one step closer to his political demise. “You could feel it in the room, this tension — and then the relief,” said a person who watched the men sign just before midnight on Wednesday. “Unforgettable.”

The unlikely trio, backed by 61 members of parliament, will try within the week to pass a vote in parliament that would dethrone Netanyahu, 71, from his 12-year reign as Israeli premier.

The vote would make Bennett, an ultra nationalist who once described the Palestinian issue as “shrapnel in the butt”, and has had to deny leaked comments from a cabinet meeting that as an army commando “he had killed a lot of Arabs”, the first religious Jew to hold the prime minister’s office.

“The irony of such an ostensibly rightwing, hawkish politician leading a government that has centrists, left-wingers and even Arabs in it is pretty strong,” said Anshel Pfeffer, author of Bibi: The Turbulent Life and Times of Benjamin Netanyahu. “It shows you two things — the need felt by so many politicians to replace Netanyahu has become such a burning motivator, but also that Bennett is lot more pragmatic than his quotes would suggest.”

It is not clear yet that they will succeed or, if they do, how long they can hold the coalition together, or what such a disparate group can achieve. If they fail, the country faces a fifth election in two years, after the previous four failed to deliver a clear result.

If the vote passes, Netanyahu, a divisive leader who has split the Israeli public, will end up in opposition while simultaneously in the defendant’s chair for his ongoing trial for corruption. He denies all charges.

The photograph of the three men was on the front of nearly every newspaper — for those in the pro-Netanyahu camp, such as the ultraorthodox Jewish minority, one headline read “Faces of Shame”. One headline on Thursday morning read “Torch Bearer”, a play on Lapid’s surname, and a nod to his parliamentary agility — corralling eight parties into a single bloc, while sacrificing his own goals of becoming prime minister to convince Bennett to play ball. If the coalition holds, Lapid will become prime minister in two years’ time.

After a month of talks, interrupted by a two-week conflict with Palestinian militants Hamas that briefly scuppered all hope of a deal, Lapid called the Israeli president, Reuven Rivlin, just 38 minutes before Wednesday’s midnight deadline.

The president was at a football match in Jaffa, the mixed Arab-Jewish neighbourhood that had just two weeks ago been gripped by some of the worst communal violence in the country’s history. Get a vote scheduled and get it done quick, the president told Lapid, according to two people privy to the call.

The urgency is in part because Netanyahu has already begun to attack what he calls a “dangerous leftwing government”, painting the concessions made for Abbas’s support as a betrayal of Zionism.

“There is no overstating the historic breakthrough of having an Arab party helping to form a government in Israel — all the more important because the partnership is with a far-rightwing party,” said Dahlia Scheindlin, a pollster and adviser to Israeli parties who has worked on eight previous campaigns.

Abbas broke from the other parties that represent the Palestinian citizens of Israel, a fifth of the population, to leverage a role as tiebreaker. “Abbas really is the star of the story,” said Roni Rimon, a veteran political strategist who has worked with Netanyahu “And now, he has no choice but to make this work — if it doesn’t, he is also finished.”

Abbas’s demands, unchanged since Ra’am’s four seats in March elections left it kingmaker, were two-fold — that his party would be treated with respect, and his support would be rewarded with material benefits for Israel’s Muslim communities.

Those gains, negotiated with Lapid and Bennett until the last minute while Netanyahu kept calling his phone, include as much as $1.5bn a year for the Arab-dominated north and the official recognition of Bedouin villages in the Negev desert to stop their demolition.

Bennett “sold out the Negev to Ra’am”, Netanyahu said on Twitter on Thursday, before holding an emergency meeting with his allies to try to block the coalition.

Meanwhile, Lapid moved swiftly to vote in a new speaker of the Knesset — the current speaker, an ally of Netanyahu’s, could delay the vote until about mid-June. If successful, the vote — and an end to the drama — could be as early as Monday.

“The Israeli public is craving to see something that reflects partnership, a willingness to compromise, maturity and unity — in the past these were slogans, but now there is a desperate need for them,” Scheindlin said.