Israel’s Supreme Court struck down a key component of Prime Minister Benjamin Netanyahu’s contentious judicial overhaul Monday, delivering a landmark decision that could reopen the fissures in Israeli society that preceded the country’s ongoing war against Hamas.

The planned overhaul sparked months of mass protests, threatened to trigger a constitutional crisis between the judicial and legislative branches of government, and rattled the cohesion of Israel’s powerful military.

Those divisions were largely put aside after Hamas militants carried out a bloody cross-border attack in southern Israel on Oct. 7, triggering a war that has raged in Gaza for nearly three months. But Monday’s court decision could reignite those tensions even while the country remains at war.

Justice Minister Yariv Levin, a Netanyahu ally and the architect of the overhaul, lambasted the court’s decision, saying it demonstrated “the opposite of the spirit of unity required these days for the success of our soldiers on the front.”

The ruling “will not discourage us,” Levin said without indicating whether the government would try to revive his plan in the short term. “As the campaigns are continuing on different fronts, we will continue to act with restraint and responsibility,” he said.

In Monday’s decision, the court narrowly voted to overturn a law passed in July that prevents judges from striking down government decisions they deem “unreasonable.” Opponents had argued that Netanyahu’s efforts to remove the standard of reasonability opens the door to corruption and improper appointments of unqualified cronies to important positions.

The law was the first in a planned overhaul of the Israeli justice system. The overhaul was put on hold after Hamas militants carried out their Oct. 7 attack, killing some 1,200 people and kidnapping 240 others. Israel immediately declared war, and is pressing forward with an offensive that Palestinian health officials say has killed nearly 22,000 people in Gaza.

In an 8-7 decision, the Supreme Court justices struck down the law because of the “severe and unprecedented harm to the core character of the State of Israel as a democratic country.”

The justices also ruled 12-3 that they had the authority to overturn so-called “Basic Laws,” major pieces of legislation that serve as a sort of constitution for Israel.