Few recent events in the Israeli-Palestinian conflict have been as wildly controversial and polarizing as the release of the Goldstone report, a United Nations-sponsored study prepared in the aftermath of Israel's devastating, 3-week-long assault on the Gaza Strip in the winter of 2008-09.

The report was the work of a U.N. fact-finding mission chaired by Richard Goldstone, a former justice of South Africa's highest court. Although Israel had publicly defended Operation Cast Lead as a tough but legitimate response to months of cross-border rocket attacks by Hamas militants, Goldstone and his colleagues saw it differently: They concluded that Israel had intentionally targeted civilians in "a deliberately disproportionate attack designed to punish, humiliate and terrorize a civilian population." A blunt, no-holds-barred broadside against Israel, the report was dismissed as biased and exaggerated by the government of Prime Minister Benjamin Netanyahu, which felt it gave moral support to those seeking to "delegitimize" the Jewish state. But it was taken extremely seriously by many others, because of Goldstone's respected mainstream credentials and the U.N.'s imprimatur, and because about 1,400 Palestinians were killed during the assault, compared with 13 Israelis.

For much of the world, that's where the story ended. Until Friday, that is, when, in a bizarre denouement, Goldstone himself disavowed one of the central claims of his report. In an op-ed article in the Washington Post, Goldstone shocked supporters and opponents alike by saying that he no longer believes that Israel intentionally killed civilians in Gaza and that "if I had known then what I know now, the Goldstone report would have been a different document."

Well, uh, OK. Acknowledging one's mistakes is generally considered a virtue. But is it really that easy? The original report contained 575 pages of damning details — attacks on mosques, hospitals, apartment buildings, refugee shelters. The fact-finding mission made three trips to the region over four months, conducted 188 interviews, reviewed 300 reports, solicited testimony and held public hearings. In case after case, the final report alleged that Palestinian civilians were targeted by Israel in violation of a host of international laws. But now the chairman of the panel says … never mind?

Goldstone explains his new position as follows: When he and his colleagues wrote that Israel had deliberately targeted civilians, it seems, they didn't really have solid evidence. Rather, he says, they "had no evidence on which to draw any other reasonable conclusion" (partly, he says, because the Israeli government did not cooperate with the investigation). Now, as a result of Israel's subsequent investigations into some 400 allegations of misconduct, he sees that the facts "indicate that civilians were not intentionally targeted as a matter of policy." If only the Israelis had cooperated with his investigation from the start, he suggests, this unfortunate misunderstanding might never have occurred!

Goldstone gives only one example in his article: the killing of more than 20 members of the Samouni family. The report says the deaths occurred at 6:30 a.m. on Jan. 5, 2009, as a result of "projectiles" apparently shot from Apache helicopters. Goldstone and his colleagues visited the site and interviewed numerous witnesses, concluding, among other things, that the "conduct of the Israeli armed forces in these cases would constitute grave breaches of the Fourth Geneva Convention in respect of willful killings and willfully causing great suffering to protected persons and as such give rise to individual criminal responsibility."

Now, however, Goldstone says that the shelling was "apparently the consequence of an Israeli commander's erroneous interpretation of a drone image" and that an Israeli officer is under investigation for having ordered the attack.

Goldstone's flip-flop is fascinating but mystifying, and his explanation is utterly insufficient. Deliberately killing civilians is a crime of war under international law. If civilians die, by contrast, as "collateral damage" in a legitimate operation against a legitimate military target, that's a very different thing — a horrible and tragic but sometimes unavoidable reality of armed conflict. At the very least, Goldstone needs to offer substantially more explanation than was available in his brief op-ed article. If he honestly believed his initial assertions but now has been persuaded as a result of Israel's follow-up investigations that he was wrong, then he ought to make the world aware of the facts that changed his mind. (While he's at it, he might let us know whether it was perhaps irresponsible to have made such sweeping assertions in the first place.)

On the other hand, "intentionality" is only one of the allegations in the Goldstone report. What are we to make now of all the other charges? What about the charge that Israel's military applied "disproportionate force," and that it failed to "take all feasible precautions" to avoid and minimize loss of civilian life? How about the allegations of "unlawful and wanton" destruction of property, not justified by military necessity? What about the victims denied access to ambulances and medical care? Are we to throw all of these serious charges out the window as well, or just the ones that suggest that Israel intentionally targeted civilians?

Israeli officials understandably feel both frustrated and vindicated by Goldstone's disavowal of one of his own chief findings. The report was a public relations catastrophe for Israel, and it's no surprise that Netanyahu now wants the entire document officially withdrawn. On the other side, those who agreed with the report's conclusion that the Gaza war was punitive and disproportionate are now unsure what to believe.

The charges leveled by the Goldstone report were extremely tough — tough enough to help reframe the Israeli-Palestinian debate around the world. If any of them were wrong, then Goldstone owes the world a detailed explanation so that the truth can be revealed.