JERUSALEM — Israel’s Labor party elected political newcomer Avi Gabbay as its leader Monday hoping to inject new blood into the movement that steered the country in the decades after independence but has been shut out of power for 16 years.

Labor led the Jewish state for its first three decades, leaving its mark on all aspects of Israeli society through wars, crises and the pursuit of peace. But it has not governed since then Prime Minister Ehud Barak was defeated in 2001 following a failed attempt to reach peace with the Palestinians.

“This is the day hope won,”Gabbay said in his victory speech. “The day of returning to our senses. The day of returning to our values.”

He said his campaign to oppose Prime Minister Benjamin Netanyahu and “replace the government in Israel” starts Tuesday.

Gabbay, 50, won by a small margin in a runoff vote against Amir Peretz, a former party leader and defense minister.

The winner called on Peretz to “join forces,” saying his experience is needed.

Peretz said he phoned Gabbay to congratulate him. He said he will help him and the party “on the journey to replace Netanyahu, which we really hope will become reality.”

Gabbay is relatively unknown in Israeli politics. He served a brief stint as environment minister under Netanyahu’s right-wing coalition. He then resigned in protest last year and joined Labor when Netanyahu ousted Defense Minister Moshe Yaalon in favor of nationalist Avigdor Lieberman.

A former telecom executive, Gabbay stresses his humble beginnings before his rise to prominence in the business world as the seventh of eight children born to immigrants from Morocco.

Labor still has a long way to go before returning to its former glory as the party of David Ben-Gurion, Golda Meir and Yitzhak Rabin. The past 16 years have been a downward spiral as the public has grown disillusioned with its dovish message of Middle East peace amid Palestinian violence and regional upheaval.

Labor’s early leaders of European, or Ashkenazi, descent took a paternalistic attitude toward Jewish immigrants from Arabic-speaking countries in the Middle East and North Africa. Many of these immigrants, known as Mizrahi Jews, were sent to shantytown transit camps and largely sidelined.

They found their political savior in the Likud Party’s Menachem Begin, who cultivated an outsiders’ alliance that appealed to their sense of deprivation. With strong backing from Mizrahi Jews, he swept to power in 1977.

In many ways, Labor has been fighting back ever since, rarely wresting control from Likud.

Barak, the last Labor prime minister, tweeted “Revolution!” after Gabbay’s win. He added that Netanyahu “is sweating and rightly so.”

There was no immediate comment from Netanyahu’s office.

The next national election isn’t scheduled until late 2019, but opinion polls indicate Labor could win just 10 to 15 seats in the 120-seat parliament, making it Israel’s fourth- or even fifth-largest party.

The new Labor chairman would usually be the country’s opposition leader, a formal role that affords meetings with visiting foreign dignitaries and high-profile speaking opportunities. But Gabbay is not a member of parliament and in his victory speech he asked former Labor chairman Isaac Herzog if he would take the role of opposition leader. Herzog lost the party leadership post in an earlier round of voting last week.