Israel's Supreme Court began a hearing Tuesday on petitions to strike down a major element of the hard-right government's controversial judicial overhaul, which has triggered mass protests and divided the nation.
A full 15-judge panel of the top court convened to hear pleas against the amendment of the so-called "reasonableness clause" that the government of Prime Minister Benjamin Netanyahu passed through parliament in July.
The amendment limits the powers of the top court to review and sometimes overturn government decisions, which opponents say paves the way to authoritarian rule.
Since the government unveiled the plans in January, opponents have rallied weekly in their tens of thousands in cities across Israel.
Thousands of protesters chanting "Democracy, Democracy," rallied in West Jerusalem on the eve of the hearing.
"The amendment to the basic law that will be debated in court today is not a basic law, it's an irresponsible document," opposition leader Yair Lapid said on Facebook.
Netanyahu's administration, a coalition between his Likud party and extreme-right and ultra-Orthodox Jewish allies, argues that the legal changes are needed to rebalance powers between politicians and the judiciary.
Justice Minister Yariv Levin, the main architect of the reforms, said the Tuesday hearing was a "fatal blow" to democracy since for the first time the court was considering striking down a basic law, legislation that in Israel takes the place of a constitution.
"The court, whose judges select themselves behind closed doors and without a record, is placing itself above the government, the parliament, the people and the law," he said in a statement.
"This is absolutely against democracy. It means that the court has no checks and balances. It's a single ruler."
Israeli media have reported some moves toward a compromise between the government and the opposition, while Netanyahu said Monday he aimed to "reach a national consensus to restore the balance of power" between the branches of government.
Israel does not have a constitution or upper house of parliament, and the "reasonableness" law was put in place to allow judges to determine whether a government had overreached its powers.
The Supreme Court used the measure in a high-profile ruling that barred Aryeh Deri, a Netanyahu ally, from serving in the Cabinet because of a tax evasion conviction.
Opponents accuse Netanyahu, who is on trial on corruption charges he denies, of trying to use the proposed legal overhaul to quash possible judgments against him.
He rejects the accusation.