For 33 years, Eitan Herzel has proudly dovetailed his career in Israel’s vaunted tech industry with reserve duty in an elite commando unit of the Israeli military.
Several times a year, for a total of roughly 30 days, Mr. Herzel left his job as a tech engineer to report for duty — initially as a fighter and then to guide the selection and training of new commandos.
That life of service came to a sudden end on Tuesday when Mr. Herzel wrote to his commander to resign in protest over the far-right government’s decision to limit judicial power, which he sees as an assault on democracy.
“I have an agreement, like every soldier, between me and the country,” said Mr. Herzel, 55. “Israel is a country that is both Jewish and democratic,” he added. “If it becomes only Jewish and not a democracy, then that agreement is broken, and I can’t serve anymore.”
More than 10,000 reserve pilots, intelligence officers, commandos, military instructors, army medics and infantrymen had threatened to resign from volunteer duty if the government pressed ahead with the judicial overhaul bill that was approved by Parliament on Monday.
It is too soon to tell how many will make good on their promises, like Mr. Herzel, because reservists are called up on a rolling basis. But estimates provided by reservists prominent in the protest movement suggest that at least 1,000 have so far made the wrenching decision to resign.
To those leaving the reserves, and for most Jewish Israelis, the military is a melting pot that unifies citizens from most social, ethnic and political backgrounds around a shared and hallowed national project: the defense of the Jewish state, within living memory of a genocide that killed millions of Jews. The turmoil surrounding the reservists’ resignations casts doubt on that sense of common mission.
And while the number of resignations represents a small minority of reservists, some serve in critical positions, and the losses have already raised fears about the combat readiness at what is considered the most tumultuous moment for the Israeli military, outside of a war, since its founding in 1948.
For now, the worries center mostly on the air force, given its reliance on reservist pilots who are often more experienced than those in the active military. Resignations forced at least one squadron of helicopters at a flying school to be grounded because of a sudden dearth in flying instructors, according to a senior officer and pilot in the air force reserve who requested anonymity to discuss a delicate subject.
The passage of the law — which pits those with a more secular and pluralist vision for the country against those with a more religious and nationalist view — has caused a cascade of social unrest. Sporadic clashes broke out between the government’s supporters and critics on the day of the vote, and on Friday, the top civil servant in the Education Ministry resigned. Business leaders say they are weighing whether to divest from Israel, and many Israelis say they are considering emigrating.
But perhaps the most consequential immediate effect of the law, in practical and emotional terms, is on the morale, capacity and unity of the military reserve.
The law removes one of the tools the Supreme Court uses to overrule government decisions. The government — an alliance of ultranationalists and religious conservatives led by Prime Minister Benjamin Netanyahu — says this improves democracy by strengthening the power of elected lawmakers.
But the departing reservists say that it removes a key check on government overreach, paving the way for a more autocratic and religious society — and that this is not the kind of system they signed up to defend.
Opponents of their decisions say the military threat against the nation should trump all other concerns, with one group that says it represents more than 20,000 reservists, the Israel Defense And Security Forum, calling the reservists’ protest “a quiet military coup.”
Most young Jews serve at least two years in the military after leaving school. (Israel’s Arab and ultra-Orthodox Jewish minorities, collectively a third of the country’s population of nine million, are not obligated to serve). After that, around a half-million adults — roughly 5 percent of Israelis — return to the military, some of whom serve roughly a month a year or more. Israeli reservists often serve with the same people they fought alongside as conscripts, creating strong bonds that span social divides and last decades.
It is this feeling of togetherness and shared purpose that had been eroded in recent months as the government pressed ahead with the judicial plan.
In the past, most Israelis “agreed on the big story of what’s the meaning of being here in this very little spot in the Middle East,” said Gur Elroey, the rector of Haifa University, who resigned this past week from a reserve unit that searches for soldiers missing in action.
The law ends that shared mission, Professor Elroey said, because it shows that the government and the opposition have incompatible visions of Israel’s democracy.
“The Israelis that are supporting Netanyahu — the messianic, the ultra-Orthodox — are not part of my society,” said Professor Elroey, 55. “They are not my brothers anymore. Solidarity in Israel does not exist anymore.”
Exacerbating this fissure is that key figures in the government did not do military service, and are therefore perceived as trying to change the nature of the state while relying on others — the military and the reservists — to protect it.
Two of the five parties in the ruling coalition represent ultra-Orthodox Jews, most of whom are allowed to study religious texts instead of serving as conscripts. Another key advocate for the legal changes is the national security minister, Itamar Ben-Gvir, who wanted to serve in the army as a teenager but was barred because of his extremist activism.
“We are the Israelis who go to the army, we are part of what makes the Israeli economy strong,” Mr. Herzel said. But at least a quarter of the coalition “didn’t serve the army, and they don’t educate their kids to go to the army.”
Some reservists also resigned out of their fears that this government is now more likely to order actions that could be seen as breaking international law, and they also want to avoid the possibility of prosecution in international courts.
Mr. Ben-Gvir, the security minister, has been convicted of racist incitement and supporting a terrorist group. Bezalel Smotrich, a junior minister in the Defense Ministry, recently called for the state to “erase” a Palestinian town at the center of recent violence involving Israeli settlers.
“We’re really afraid of the orders that those guys will be giving,” said Nir Avichai Cohen, a major in a reserve infantry division, who resigned this past week. “One of the first to suffer will be the Palestinians.”
And there are other tensions, with many reservists saying it is not their place to use their position to influence a civilian government.
“It breaks all bounds,” said Shay Kallach, a former fighter pilot who serves as a reservist at the air force command center. “When you refuse to protect Israel because there is a government that you’re not satisfied with — it’s a disaster.”
The military has not released data about the number of resignations, nor an assessment of how it affects battle readiness.
But around 700 airmen, including roughly 230 combat pilots and instructors, have resigned, according to the senior officer who spoke about helicopter training and another senior pilot in the reserves, who spoke on the condition of anonymity in order to discuss sensitive information.
A large number of withdrawals could affect Israel’s ability to conduct air raids. Israel’s regular strikes in Gaza and Syria, patrol missions over Israel and surveillance missions over Lebanon and the occupied West Bank are frequently led by reserve pilots and drone operators.
Within the military high command, there are fears that the reservists’ protest has begun to affect the cohesion of the standing army.
“It is our duty to prevent these cracks from widening,” the military chief of staff, Lt. Gen. Herzi Halevi said in an unusually frank statement to the Israel Defense Forces last Sunday.
“This is the only way we can maintain the I.D.F.’s purpose: to protect the country and ensure its existence,” he added.
Isabel Kershner, Hiba Yazbek and Jonathan Rosen contributed reporting from Jerusalem.