Thousands of Israeli doctors walked out of work, labor leaders threatened a general strike and senior justices rushed home from a trip abroad Tuesday, a day after the government approved a law weakening the country’s supreme court that critics say will erode the system of checks and balances.

Four leading Israeli newspapers covered their front pages in black ink — an ominous image paid for by an alliance of high-tech companies. The only words on the pages were in a line at the bottom: “A black day for Israeli democracy.”

Monday’s vote — on the first of a series of measures that make up Prime Minister Benjamin Netanyahu’s divisive judicial overhaul — reverberated across the country. It came despite seven months of fierce popular resistance, Netanyahu’s promises of an eventual compromise and a rare warning against the overhaul from Israel’s closest ally, the United States.

The bill was unanimously passed by the governing coalition, which includes ultra-nationalist and ultra-religious parties, after the opposition stormed out of the hall shouting “Shame!” But opponents say they are not done fighting it: Civil rights groups submitted petitions to the Supreme Court, calling for the new law to be overturned, and protests roiled the country’s streets overnight.

Hundreds of thousands of people fanned out in Tel Aviv, burning tires, setting off fireworks and waving national flags. In central Jerusalem, police mounted on horses unleashed water cannons and a foul-smelling spray at protesters, arresting nearly 40 people. At least 10 officers were assaulted and injured, they said.

Israel is now hurtling into uncharted territory against the specter of further social and political unrest. Thousands of officers in the military reserves have announced they’ll no longer turn up for voluntary service — a blow that could undermine the country’s operational readiness. High-tech business leaders are considering relocation.

The overhaul also threatens to strain ties with the Biden administration, jeopardize the country’s new alliances with Arab states and deepen Israel’s conflict with the Palestinians, analysts say.

“I think this country is going to either split into two countries or be finished altogether,” said Yossi Nissimov, a protester in a tent city set up by demonstrators outside of the Knesset, or parliament, in Jerusalem.

The vote on the law came just hours after Netanyahu was released from the hospital, where he had a pacemaker implanted, adding another dizzying twist to an already dramatic series of events.

The Israeli Medical Association, which represents nearly all of the country’s doctors, announced they would strike en masse Tuesday across the country, with only emergencies and critical care in operation.

“The vast majority of physicians know they will not be able to fulfill their oath to patients under a regime that does not accept the role of reason,” said Hagai Levine, chairman of the Israeli Association of Public Health. He was referring to the law passed Monday that prevents the Supreme Court from using the standard of “reasonableness” to strike down government decisions.

“This overhaul will damage the public health and the health care system in Israel,” Levine said, adding that already over 1,000 physician members have asked for relocation abroad since the law passed.

Nationwide General Strike in Works

Israel’s largest labor union, the Histadrut, which represents some 800,000 workers, said Tuesday that it would convene in the coming days to plan a nationwide general strike.

The chief justice of the Supreme Court, Esther Hayut, along with five other senior justices, cut short a trip to Germany in order to deal with the crisis, the court’s spokesperson said. The justices were expected to land Tuesday night, a day earlier than expected, to discuss petitions against the overhaul.

But any move by the court to strike down Netanyahu’s new law could lead to a constitutional crisis and put the justices on an unprecedented collision course with the Israeli government.

Supporters of the judicial overhaul say that the powers of unelected judges should be curbed to boost the powers of elected officials.

Opponents say that it will undermine Israeli democracy and erode the country’s only check on majority rule in a system where the prime minister governs through a coalition in parliament — in effect giving him control over the executive and legislative branches of government.

As a result, the Supreme Court plays a critical oversight role.

Protesters also fear that the overhaul is fueled by the personal grievances of Netanyahu, who is currently on trial on charges of bribery, fraud and breach of trust.

While protesters represent a wide cross section of society, they come largely from the country’s secular middle class. Netanyahu’s supporters tend to be poorer, more religious and live in West Bank settlements or outlying rural areas.

The judicial overhaul, in deepening Israel’s social and religious divisions, has laid bare “a struggle for Israel’s basic values,” said Israeli historian Tom Segev.

“Never in the history of Israel did we have a government that was so dangerous to the very democratic foundations of society,” he said.