During its six decades of existence, Israel has maintained a shaky alliance with its ultra-Orthodox Jewish minority that allowed most religious men to avoid military service, attend separate schools and get paid by the state to study the Bible instead of entering the work force.
But this system is coming under new scrutiny, pressured by a series of Supreme Court rulings, an ambitious education minister and the hugely unpopular cost of sustaining a fast-growing ultra-Orthodox population that has few skills for the 21st century and now accounts for one in four Jewish first graders - and growing.
The vitriolic debate has created the first serious threat to Prime Minister Benjamin Netanyahu's governing coalition. His ultra-Orthodox partners are threatening to topple the government if subsidies to their constituents are cut.
The dispute goes far beyond money, touching on the character of the Jewish state in a modern world and the ultra-Orthodox community's place in it.
Many secular Israelis see the ultra-Orthodox, with their large families, as a financial drain and are growing less willing to subsidize them when half of their men don't work - preferring to study the Torah - and their children are taught little math and science. They warn that if the system continues it could ultimately undermine a country that has become a high-tech powerhouse with vibrant media and culture.
Schools have emerged as a main front in the conflict.
Education Minister Gideon Saar is moving to tighten oversight of the semiautonomous ultra-Orthodox grade school system. Saar, a rising star in Netanyahu's Likud Party, is insisting that core subjects such as English, math, history and science be taught at all government-funded schools, including ultra-Orthodox ones.
Some 245,000 students - about one in every six in Israel - are enrolled in ultra-Orthodox schools from grades 1-12, according to the Education Ministry. The schools, which emphasize religious studies, are essentially run by nonprofit organizations that do not answer to the state, though they receive government funds.
Top ultra-Orthodox rabbis held an emergency meeting last week to oppose Saar's moves. The rabbis say the schools are training spiritual leaders and that the measures undermine an emphasis on biblical studies they say has allowed the Jewish people to survive for thousands of years.
"Education is not just about knowledge, it is also about values," said ultra-Orthodox lawmaker Uri Maklev. "We teach the value of the Bible as the ultimate value. They teach children to be infidels and anti-religion."
Under the current system, ultra-Orthodox schools must teach the core grade-school curriculum in proportion to how much state money they receive. Fully funded ones must teach it in full. A school receiving 50 percent funding needs to teach only half.
In the past, oversight has been lax. But an Education Ministry survey found that nearly 20 percent of ultra-Orthodox schools are not living up to their obligations, and Saar has informed them their funding will be slashed. He has also hired more inspectors.
The ultra-Orthodox, also known as haredim, make up 10 percent of Israel's 7.6 million people. But they have long served as kingmakers in Israel's fractious parliamentary system, giving them considerable political clout.
With generations of coalition governments dependent on their support, they have won outsized subsidies for schools, child support and welfare payments to allow adult men to spend their days studying in seminaries. The government's annual budget for supporting the seminaries, for example, runs at around $275 million, including operating costs and the stipends that go to married seminary students. The haredim's exemption from military service - which is compulsory for other Jewish Israelis - has added to the resentment.
Ultra-Orthodox men are easily identified by their black suits, long beards and sidecurls. They and their families typically live in isolated neighborhoods and often have little interaction with the outside world.
"If they want to live in a ghetto, fine, but why should the state pay for it? As long as the state is paying, it has to have a say," said Yossi Sarid, a former education minister.
High birth rates, voluntary unemployment and limited modern skill sets have left the ultra-Orthodox sector among the poorest in Israel.
According to a 2007 survey for the Central Bureau of Statistics, 53 percent of men and 51 percent of women in the ultra-Orthodox community said they work, compared with 93 percent and 86 percent of their secular counterparts.
Earlier this year, Israel's Supreme Court ruled that the seminary stipends discriminate against university students.
Ultra-Orthodox parties say they will quit the government if alternative legislation is not approved to keep stipends. Netanyahu would lose his parliamentary majority if they bolt.
This week, a religious lawmaker introduced a bill that get around the court ruling by giving allowances, valued at around $33 million, to all students who are married with at least three children, have no other income and no car. Those conditions overwhelmingly favor the ultra-Orthodox, ensuring stipends for 11,000 seminary students - and only about 200 university students.
An outcry followed. University students poured into parliament to lobby against the bill and have taken to the streets in protest. Many political leaders say they will oppose the measure. Netanyahu on Sunday ordered a committee to find a compromise within two weeks.
In an interview Monday in the Haaretz daily, Saar called the bill a blow to equality, "to Israel's economy and to the integration of the ultra-Orthodox into the work force."
The public appears to agree. A Smith Institute survey found that 75 percent of Israeli Jews favor reducing subsidies. The poll, conducted for the religious equality group Hiddush, surveyed 800 people with a margin of error of 3.4 percentage points.
