Prime Minister Benjamin Netanyahu has made clear that he wants Lieberman to return to the post. Since a parliamentary election in January, Netanyahu has left the job vacant for his political ally while awaiting a verdict.
Following the ruling, Netanyahu called Lieberman to congratulate him and said he was looking forward to Lieberman's "return to the government table," according to a statement from the premier's office.
An Israeli official said Netanyahu would ask his Cabinet on Sunday to approve Lieberman's re-appointment as foreign minister. The parliament would then vote on it, possibly as soon as Monday, the official said, speaking on condition of anonymity because Netanyahu has not spoken publicly on the matter.
The 55-year-old Lieberman, who immigrated to Israel from the Soviet Union more than 30 years ago, has gained popularity through a hard-line stance that has appealed to nationalistic Israelis.
He has questioned the loyalty of Israel's Arab minority, expressed doubt about the Palestinians' commitment to peace and confronted Israel's foreign critics. The tough-talking message has at times alienated Israel's allies while also making him an influential voice at home.
During his stint as foreign minister, he pushed a series of legislative proposals that critics said were discriminatory against Israel's Arab minority, including a failed attempt to require Israelis to sign a loyalty oath or have their citizenship revoked.
He also embarrassed Netanyahu by expressing contrary views to the government, including his skepticism over the odds of reaching peace with the Palestinians.
In a 2010 speech at the United Nations, Lieberman suggested redrawing Israel's borders to shift large numbers of Israeli Arab citizens to Palestinian control as part of an intermediate arrangement that could last for decades. Netanyahu's office was forced to distance itself from the speech.
Wednesday's verdict coincided with a visit by U.S. Secretary of State John Kerry, who is in the region trying to revive faltering peace talks.
A return to the Foreign Ministry will give Lieberman an important voice in Israeli discussions on the talks. Although Netanyahu ultimately makes the final decisions, Lieberman could potentially make things difficult for the prime minister.
Lieberman led his Yisrael Beitenu party into a merger with Netanyahu's Likud movement before January's election. But the alliance, meant to solidify a victory by Israel's hardline nationalist bloc, backfired and fared poorly. Lieberman is now considering whether to dissolve the partnership.
If they stick together, Lieberman will remain an important force within the ruling party who could rally fellow hardliners against any significant peace moves.
If Yisrael Beitenu breaks away, Lieberman could try to use his influence to force Netanyahu to reshape his coalition by bringing in hardline religious parties while expelling more moderate elements. Lieberman could even leave the coalition, potentially robbing Netanyahu of his parliamentary majority.
Avraham Diskin, a political scientist at the Hebrew University, said Lieberman is "skeptical and doesn't believe" in a peace agreement. "But I don't think the negotiations will stop because of it."
He said Netanyahu always has the option of reaching out to the moderate opposition if there is progress in the peace efforts.
With those negotiations making no tangible progress, however, Lieberman has little incentive to abandon Netanyahu. Many analysts believe he is in fact positioning himself to be a future prime minister whenever Netanyahu, 64, steps down.
"What is clear and known to all in politics is that Lieberman wants to be prime minister one day," political commentator Yossi Verter wrote in the Haaretz daily's website. "In order to get to the lofty position, he must behave accordingly: responsibly, with discretion, as a leader who sees the big picture and at the same time to try to capture the chairmanship of the Likud in a post-Netanyahu era."
At the same time, Lieberman has sometimes shown signs of pragmatism. For instance, he has said he would support dismantling some Jewish settlements, including the one where he lives, under his plan to redraw borders.
Yehuda Ben-Meir, a political analyst at the Institute for National Security Studies and former deputy foreign minister, said Lieberman may show surprising leniency regarding peace negotiations.
"The accepted opinion is that he's very hawkish and he will try to disrupt and prevent an agreement," said Ben-Meir. "But from someone who knows him personally ... Lieberman could surprise."
