It's difficult to say exactly when the taboo was broken.
Was it when former US President Jimmy Carter put the word "apartheid" in the title of his book to sound a warning to Israel? Was it when South African Archbishop Desmond Tutu said the situation in the Palestinian territories struck him as worse than the white racist regime he'd lived under? Or was it when the A-word began spilling from the lips of former Israeli prime ministers?
A decade ago, pointing out the parallels between the policies of successive Israeli governments and the political system of the old South Africa generally invited abuse and scorn. Uri Davis did it in his landmark book Israel: An Apartheid State in 1987. Others ventured there too, but pro-Israel activists on the right and left worked hard to delegitimise discussion of the myriad of similarities by dismissing it as unworthy of serious debate or claiming it had the stink of anti-Semitism.
I know this because in 2006, as a reporter for the Guardian who worked in Johannesburg and then Jerusalem, I explored the apartheid parallel in a couple of long articles (to be found here and here) prompting a predictable barrage of denunciations. The soon-to-be editor of London's Jewish Chronicle compared me to the Holocaust-denying leader of Iran: "Other than the desire to drop a nuclear weapon on Israel, there appears to be not a cigarette paper between McGreal and President Ahmadinejad."
The Board of Deputies of British Jews sent a delegation to confront the Guardian's editor and created a small stir by swearing at him.
A pro-Israel pressure group in the US, the Committee for Accuracy in Middle East Reporting in America (Camera), filed the longest submission in the British Press Complaints Commission's history, running to around 35,000 words. It was a brazen attempt to impose an invented history, even going so far as to deny Israel's persistent and well documented obsession with demographics and the number of Arabs in its orbit, as well as laying amorphous charges of "denying the historic rights of the Jewish people" and "showing contempt for Zionism".
Tellingly, Camera – which bears the hallmarks of a Jewish supremacist organisation in its contorted defence of settlers and occupation – argued that discrimination against Arabs with Israeli citizenship was legitimate if it was by private organisations.
The PCC ruled against the group on every part of its complaint and added a heart-warming coda about freedom of speech. That touched on the real issue. Camera wasn't interested in accuracy. It wanted to harass, intimidate and shut down any talk about Israel and apartheid.
These were standard tactics.
Camera took a full page advert in the New York Times to denounce Carter for his book, "Palestine: peace not apartheid" and set about harassing his publisher. A group of American Jews filed a federal lawsuit seeking millions of dollars in damages on the grounds that the former president's book "misled" readers with information that "defamed Israel".
Archbishop Tutu, a courageous leader against apartheid, was the target of a sustained vilification campaign. Alan Dershowitz, the American constitutional lawyer and self-appointed defender of Israel who once said that "there is a special place in hell for Jimmy Carter", accused Tutu of being an anti-Semite and "one of the most evil men in the world".
This kind of aggression was driven by particular alarm over the sticking of the apartheid label on Israel because it challenges the myth that decades of occupation, settlements and denial of many basic human rights are a necessary evil that the Palestinians have brought on themselves. If Israel is deliberately imposing a form of apartheid, then something else is behind it; racism.
The attempt to hold the line that there are no grounds for discussion of apartheid in Israel was breached fatally when the country's own political leaders, former intelligence chiefs and parts of its media began touting the idea. They included former prime ministers Ehud Olmert and Ehud Barak. Barak warned that so long as Israel governs the Palestinians and Palestinians don't have a vote, "that will be an apartheid state."
Ami Ayalon, the ex-head of Israel's Shin Bet intelligence service, has said that his country already has "apartheid characteristics."
The idea has even strayed into the highest levels of the US government. Last year, Secretary of State John Kerry dared to warn that Israel risked becoming an apartheid state if it didn't end the occupation. Kerry was forced to apologise for using the A-word but he did so in a manner which suggested that he regretted the political backlash not the thought.
The only thing Kerry got wrong was the tense. The risk is not of a future apartheid state. It's already here and increasingly difficult to deny. The inexorable expansion of Jewish settlements, the construction of the West Bank separation barrier to grab yet more territory and the carving out of the de facto Palestinian Bantustans are there for all to see.
Some of the most powerful politicians in Israel no longer even bother to pay lip service to a two state solution buried under a rising tide of Jewish nationalism and overt denial of the right of Palestinians to a say in the system that rules over them.
In the face of this, the perennial apologists for Israeli government policies have set up a new defensive line. Some are now prepared to acknowledge that there is indeed something resembling apartheid in the West Bank but insist that there are no parallels within Israel proper. It's a convenient distinction because it perpetuates the lie that systematic discrimination in the occupied territories is the product of conflict with the Palestinians when it is has been rooted in Israel's treatment of its own Arab citizens for decades.
Its falsity has been made blindingly clear by Prime Minister Benjamin Netanyahu's party and its allies in government.
There has been no shortage of racists in previous Israeli administrations which tolerated ministers who advocated ethnic cleansing, who called Palestinians a "cancer" and "lice", and who made it clear that Israel's Arab citizens remained on sufferance. But they generally paid lip service to the rule of law and Israel as a democracy.
Now even that is being stripped away. Justice Minister Ayelet Shaked, a former director of Netanyahu's office, has had no compunction about expounding her views in support of the colonisation of Palestinian territory, that there should never be a Palestinian state or that the entire Palestinian people are "the enemy".
Shaked, though, represents something more. As justice minister she is at the forefront of a political movement that unashamedly subordinates Israel's already compromised democracy to the grab for land and Jewish domination.
Her particular target is Israel's Supreme Court which has had the temerity to rule that the country's Arab citizens have equal rights. Many Palestinian Israelis will tell you that they don't in practice and the highest court in the land has been cautious to ensure that its rulings do not go too far to challenge systematic discrimination. But even that has been too much.
With a background in the tech industry not law, Shaked came into office saying that she would not allow the legal system to "eat away" at the power of the politicians.
The Israeli right has grown increasingly exasperated with the Supreme Court. It was particularly angered when the court struck down a decades-old system of discrimination which permitted residents of smaller towns and villages to veto potential Arab neighbours. It was also used by the state-run Israel Lands Authority to reserve vast tracts of the country for Jews only and to keep Arab citizens confined to towns with bad infrastructure, fewer jobs and second-rate schools.
The court ruled that the system of "admissions committees" was illegal after it was challenged by a Palestinian-Israeli nurse. The decision sent a shudder through the Israeli right. Local councils cooked up new rules for residents of their towns, such as demanding service in the military, knowing that only Jews are conscripted, and requiring pledges of support for "Zionist values".
Leading rabbis issued a religious ruling forbidding houses to be rented to non-Jews. One rabbi said that it was to stop "Arabs setting down roots in Israel." Another defended the measure by arguing that "racism originated in the Torah."
The ruling coalition in Israel's parliament rushed to circumvent the court ruling, passing a law which legalised the committees and permitted towns to turn away potential residents who "fail to meet the fundamental views of the community" or do not fit into its social fabric. The loose wording of the law deliberately left room for creative interpretation.
MPs were frank about the intent. One of them, David Rotem, said that it would ensure that there were towns for "people who want to live with other Jews." He advanced the unusual argument that freedom means deciding who can live on your street. "In a democratic state," he explained, "each one of us has got to be allowed to choose who he wants to be his neighbours." Other MPs said openly that Arabs should not be regarded as full citizens.
Tel Aviv's Haaretz newspaper described the admissions committee law as an "outrageous attempt to preserve Jewish purity." A former cabinet minister put it another way. It was, he said, "a law that reeks of apartheid.".
The legal and political struggle over acceptance committees kindled a campaign to amend Israel's Basic Law, its de facto constitution, to subordinate equality of all its citizens in favour of stipulating that the Jewish majority has superior rights. Among other things, the changes would require courts to put Jewish identity before democratic considerations in cases about equal rights.
Netanyahu gave his endorsement to the change that would define Israel as "the nation state of one people only – the Jewish people – and of no other people". The right-wing economy minister and leader of the Jewish Home Party, Naftali Bennett, backed the amendment by saying that Israel should have "zero tolerance" for the aspirations of its Arab population.
Now Shaked wants to weaken the powers of Israel's Supreme Court to ensure that it does not again rule in favour of equality. At least equality for Arabs.
None of this has anything to do with occupation. It has everything to do with apartheid.
The views expressed in this article belong to the author and do not necessarily reflect the editorial policy of Middle East Monitor.