Benjamin Netanyahu's rival turned down his offer of a national unity government on Thursday (September 19).
Another abrupt shift in the changing fortunes of Israel's longest-serving prime minister.
He has just failed to win a ruling majority for the second time this year, which prompted him to make the surprise offer.
Rebuffed by Benny Gantz, whose Blue and White party emerged slightly ahead of Netanyahu's right-wing Likud in Tuesday's (September 17) elections.
Gantz has called for a "liberal" unity government -- meaning there's no place for Likud's ultra-Orthodox allies.
And he has ruled out joining forces with Likud itself while Netanyahu remains at the helm.
Gantz's election campaign zoomed in on graft charges against Netanyahu.
He denies them and faces a pre-trial hearing next month.
But the man known to his supporters as "King Bibi" looks ever more vulnerable, and losing public office would leave him further exposed.
Some sort of coalition will be needed, as is usual in Israel, since no one came close to winning a majority.
It could take weeks to form one, and many more reversals are possible.
For the Palestinians though, there may be little difference between hawkish Netanyahu and centrist former armed-forces chief Gantz.
Their campaigns were similar on many issues.
And Netanyahu's fall would be unlikely to bring significant changes on the Palestinian conflict, or relations with U.S. President Donald Trump's deeply pro-Israel administration.
Although Netanyahu highlighted his close ties to Trump during campaigning, the U.S. president has since appeared to distance himself slightly, telling reporters "our relationship is with Israel".