South Africa has taken a decision that may one day prove to have been a significant step toward peace in the Middle East. Whether this ultimately comes to pass or not, the step has already notched a kink in the juggernaut called occupation.

The South African cabinet approved a proposal “requiring the labeling of goods or products emanating from Israeli occupied territories, to prevent consumers being led to believe that such goods come from Israel,” cabinet spokesperson Jimmy Manyi said on Wednesday.

“This is in line with South Africa’s stance that recognizes the 1948 borders delineated by the United Nations, and does not recognize occupied territories beyond these borders as being part of the state of Israel.”

For the moment, the decision changes nothing on the ground, certainly nothing in the territories. It does little more than ensure that products marked “Made in Israel” actually are, and that goods produced in settlements are labeled as what they actually are, made in Israeli-occupied territory.

But the potential impact of Pretoria’s move was more than evident in the vociferous, even unsettled tone of official Israeli responses.

Throwing stones from the front porch of one of the world’s most vulnerable glass houses, Ayalon branded South Africa still “an apartheid state” and took it to task for the recent police killings of 34 striking platinum miners.

“South Africa’s apartheid is directed at the moment against Israel and also against her own miners,” Ayalon said.

In a separate statement, the Foreign Ministry said the decision brought to mind “ideas of racist nature which the government of South Africa, more than any other, should have wholly rejected.”

Aside from echoing the settlement movement’s self-characterization as a persecuted minority, the intensity of the Israeli response pointed to the precise nerve that the South African cabinet touched this week.

The decision to label products from the territories strikes with elegant nonviolence at the Netanyahu government’s single most cherished goal – obliterating for all time the Green Line border, which demarcates the occupation and divides post-1967 East Jerusalem and the West Bank from what was until recently known as Israel proper.

In a thousand ways – from influencing broadcasters to include the West Bank center of Ariel in standard weather forecasts, to mobilizing Finance Ministry slush fund payouts to help confer full Israeli university status on the settlement city’s college, to sending schoolchildren on field trips to the powder-keg enclave of Hebron – the government, loath to annex the West Bank in practice, has been tireless in its efforts to carry out an annexation of the mind.

So pervasive is the Israeli government’s effort to erase the Green Line that it underpins the ministry’s official reaction to the South African move. “What is totally unacceptable is the use of tools which, by essence, discriminate and single out, fostering a general boycott,” the ministry said, implying that there is no difference between a measure directed against settlements and a measure directed against Israel.

The importance of the South African move is that it puts Israel’s own policy to the test. Israel either considers the future of the territories and the settlements as negotiable, or it does not.

In saying that boycotting settlements is the same as boycotting Israel, the government is saying that occupation is intended to last forever, that settlement cannot and should not be opposed, and that Israeli endorsement of the principle of a two-state solution is a lie.

What the Israeli Foreign Ministry is saying, in fact, is that Israel is no more legitimate than the settlements are. Which is to say that Israel is no more legitimate than an enterprise that the even its closest ally, the United States, officially views as illegitimate.

The South African decision opposes occupation with nothing more than truth in advertising. And that is the secret of its impact.

Other countries and communities may well follow suit. They should. Consumers, among them Jews and non-Jews who support both Israel and peace moves with Palestinians, have a right to know what they are buying, and what they are buying into.