Under the unity agreement, Netanyahu, whose Likud won 36 seats in the 120-seat Knesset, is to serve as prime minister for the first 18 months. Gantz would take over from October 2021.

While some in Israel have praised Gantz as “brave” for choosing the “lesser evil”, others have ridiculed the former military chief of staff, who lacks political experience, saying that he had dealt a fatal blow to his image of integrity.

Two opposition lawmakers, Yair Lapid of the Yesh Atid party and Moshe Ya'alon of Telem, who for over a year had been Gantz's political partners, have expressed outrage and deep disappointment.

The retired general has “betrayed” his voters, “surrendered without a fight” and “crawled” into what was not a unity government, but yet another Netanyahu government, said Lapid, who along with Ya'alon broke away from the three-party Blue and White alliance – leaving Gantz with only 15 of 33 seats won in the March 2 election.

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The coronavirus crisis should not be used as an excuse to abandon democratic values and principles, Lapid has charged. 

Political scientist Jonathan Rynhold, of Bar Ilan University near Tel Aviv, sees several motivations behind Gantz’s controversial decision.

“He is genuinely a patriot, and he genuinely feels that it is the right thing to do at this time given the coronavirus,” Rynhold said.

Gantz believes that the only alternative, a fourth election, would be detrimental for Israel, he added. It would also be “bad for him personally”. After three election campaigns, the 60-year-old is tired.

“He thinks he'll lose. And he believes that, this way, he protects democracy,” because his party has the Justice Ministry – meaning he could stop bad legislation, Rynhold said. 

Netanyahu's latest right-wing and religious coalition collapsed in December 2018 over whether ultra-Orthodox yeshiva (religious seminary) students should no longer be exempt from serving in the army.

Since then, the 70-year-old has ruled at the head of a caretaker government, which has lacked democratic legitimacy.

Elections in April and September 2019 and in March 2020 all ended without a parliamentary majority, neither for Netanyahu's camp of right-wing and religious parties nor for Gantz's camp of centre, left and Arab parties.

Some political experts in Israel doubt whether Netanyahu will keep his promise to let Gantz take over the premiership.

The critical Maariv newspaper quoted an unnamed “political source” as saying that “within a few months, after the coronavirus crisis and the economic crisis are under control, and if the polls bode well for him”, Netanyahu could force early elections. 

Will Gantz give up entirely his effort to enact a law that would bar anyone under indictment from forming a government?

Under the unity deal, Gantz is to support a bill that would redefine the position of deputy prime minister, according to Israel's Channel 12 television. That would allow Netanyahu to serve in the government as deputy prime minister, in charge of relations with world leaders, once his 18 months are up.

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Currently, Israeli law disqualifies criminal defendants from holding ministerial posts. The law makes no explicit mention of an indicted prime minister – an unprecedented situation in Israel. 

Rynhold believes that Israel's longest-serving prime minister's main motivation is to avoid prison.

“This is the reason behind three elections,” the Netanyahu critic said. 

“This is what the most powerful person in the system is most concerned with.”