TEL AVIV — After 15 hours of parliamentary debate that dragged into the early hours of Tuesday, Israel's diverse new ruling coalition was unable to agree on extending a law preventing the reunification of Palestinian families divided by the Israeli separation barrier.

The vote, the first political test for the new government, exposed the rifts within a coalition that is led by a hard-right politician but is bolstered by leftist and Arab parties.

Prime Minister Naftali Bennett’s inability to extend the law, which was scuttled in a 59-to-59 deadlock vote, followed marathon negotiations and filibustering between Bennett and his coalition partners from the Arab Islamist Raam party and the leftist Meretz party, who say the policy discriminates against Israel’s nearly 2 million Arab citizens, who routinely marry across the Green Line, which represents the border between Israel and the territory it occupied in the 1967 war.

The Israeli right, including Bennett, argue that the law is necessary to prevent the entry of Palestinians into Israel who could commit terrorist attacks against the country or threaten its Jewish demographic majority.

In the end, two lawmakers from Raam abstained and one member of Bennett’s own Yamina party voted against the law, to celebratory applause from members of the opposition, later joined by cheers from members of the Arab List, who have rejected the law.

The vote meant the law would expire Tuesday at midnight.

Bennett is expected to continue negotiations with lawmakers in anticipation of a future vote, but, in the meantime, he has passed an interim arrangement extending the policy for six months and granting temporary resident status to 1,600 Palestinians who are already married to Israeli citizens.

The arrangement will also establish a committee to find solutions for the almost 10,000 additional Palestinians living in Israel on limited, military-issued stay permits.

The development represents the first major political blow to Bennett’s three-week-old coalition, which is held together by a kaleidoscope of ideologically disparate parties and is now facing off against a bellicose opposition led by former prime minister Benjamin Netanyahu, who has repeatedly vowed to topple the government that ended his 12-year rule.

Bennett accused Netanyahu, who continuously championed the law throughout his tenure and saw it pass with little fanfare, of engaging in political jockeying at the expense of the country’s security.

Netanyahu and his nationalist-religious allies voted against the citizenship law and said they would propose a more permanent basic law on immigration to accomplish the same end in the coming week.

“With all due respect for this law, the importance of toppling the government is greater. This isn’t just a law. It exposes the fault lines in this government, whose purpose is to promote an anti-Zionist agenda,” Netanyahu said at a meeting with his Likud party on Monday.

At the last minute, Netanyahu attempted to turn the event into a no-confidence vote, though the motion did not receive the required majority of 61, in the 120-seat Knesset, to pass.

Interior Minister Ayelet Shaked, whose office, in the absence of the “citizenship law,” will need to oversee Palestinian family reunification requests on an individual basis, said that Netanyahu’s “reckless decision . . . to shoot down the citizenship law will lead to 15,000 [Palestinian] requests for citizenship.”

The citizenship law was originally passed in 2003 as a temporary ordinance in response to the wave of bombings during the second intifada, or Palestinian uprising. Renewed annually ever since, it bars Palestinian citizens of Israel from extending their citizenship rights — including the ability to take out a driver’s license or obtain a legal job — to spouses who once lived in the West Bank or Gaza.

Thousands of Palestinians who have moved to live and establish families with their spouses in Israel without permanent residency are often unable to visit their families back home out of fear of being rejected at a border crossing when traveling back into Israel.

Mohammad Issa, a Palestinian Israeli meat distributor from Jerusalem, has been unsuccessfully petitioning the Israeli Supreme Court for nearly two decades to secure legal residency status for his wife, Wafa, originally from the West Bank city of Ramallah. Since she married some 20 years ago, she has been back to Ramallah only once, for an emergency surgery in a Palestinian hospital, but has missed countless other family gatherings with Mohammad, their six children, their grandchild and their West Bank-based relatives.

While members of the Arab List called Tuesday’s failed vote a “victory for thousands of Palestinian families,” Issa said that, under Bennett “and a government of racists,” he was skeptical that the status quo would really change.

“Before he was prime minister, Bennett was threatening the Arabs, talking about stealing their lands, about how he didn’t want for the two peoples to live side-by-side,” Issa said. “So good for him: He did it. What can I say?”

Sufian Taha in Jerusalem contributed to this report.