“The Labor Party voted for change.”

Though Labor currently leads the opposition bloc in the Israeli parliament, the Knesset, the party is struggling with an electorate that has shifted to the right in recent years, and a seeming lack of a charismatic political leader to reinvigorate the party base and attract new supporters. The runoff election sees two candidates with sharply different political backgrounds: Amir Peretz, a longtime politician and former party leader; and Avi Gabbay, an ex-businessman who joined Labor only months ago. Herzog has faced a barrage of criticism over his attempts to negotiate for his party to join Israeli Prime Minister Benjamin Netanyahu's right-wing coalition and over Labor’s slide in opinion polls. “They chose someone totally new and somewhat unfamiliar to the public and the voters.”

Ehud Barak, a former Labor leader, prime minister and military chief of staff who strongly endorsed Mr. Gabbay and seems poised for a political comeback of his own, described Mr. Gabbay’s win as a “revolution in Labor.” Mr. Barak added that Mr. Netanyahu and his allies would be “sweating tonight, with good reason.”

Isaac Herzog, the departing Labor chairman who won the party 24 seats in the last election to the Likud’s 30, was knocked out last week in a first round of voting. “Israelis who believe in our ideology and values, but Israelis who, for decades, have not voted Labor.”

Mr. Gabbay and Mr. Peretz, 65, from the immigrant town of Sderot near the border with the Gaza Strip, are both Mizrahi, or Eastern, Jews of Moroccan descent, and their leadership contest brought to the fore the debate over Israel’s identity and ethnic politics. Mr. Gabbay became the minister for environmental protection, but he quit after a year, saying that he did not like what he saw in government and that Mr. Netanyahu’s decision to replace his defense minister, Moshe Yaalon, with the ultranationalist Avigdor Lieberman as part of a political deal was too much to swallow.
Avi Gabbay, former minister of environmental protection in Benyamin Netanyahu's government, wins an upset victory in the primaries of the Israeli Labor Party, thus becoming leader of the opposition.