On Wednesday, Prime Minister Benjamin Netanyahu told his old friend John Kerry in Jerusalem that he was concerned about the peace process, and asked the visiting US secretary of state to “steer [the Palestinians] back to a place where we could achieve the historical peace that we seek.” John Kerry quickly responded by lauding both sides’ “good faith,” and said he was “very confident” the negotiations would succeed.

But on Thursday, he loosened the diplomatic straitjacket, and we all got a much better look at what John Kerry really thinks about progress — and blame — in the new peace effort he worked so strenuously to revive a little over three months ago. He turned directly to the Israeli and Palestinian peoples and showed them rather more of his true colors. To the prime minister, it is safe to assume, they did not look particularly blue-and-white.

For the first time since he managed to restart the talks in July, Kerry dropped his statesman-like public impartiality, and clearly spoke from the heart — and what emerged were a series of accusations that amounted to a forceful slap in the face for Netanyahu. It was a rhetorical onslaught that the prime minister cannot have expected and one he will not quickly forget.

In an extremely unusual joint interview with Israel’s Channel 2 and the Palestinian Broadcasting Corporation, a very frustrated Kerry basically blamed the Israeli government for stealing the Palestinians’ land and the Israeli public for living in bubble that prevents them from caring much about it. If that wasn’t enough, he railed against the untenability of the Israel Defense Forces staying “perpetually” in the West Bank. In warning that a violent Palestinian leadership might supplant Mahmoud Abbas if there was not sufficient progress at the peace table, he appeared to come perilously close to empathizing with potential Palestinian aggression against Israel.

“If we do not resolve the issues between Palestinians and Israelis,” Kerry warned early in the interview, “if we do not find a way to find peace, there will be an increasing isolation of Israel [and an] increasing campaign of delegitimization of Israel.

“If we do not resolve the question of settlements,” he continued more dramatically, “and the question of who lives where and how and what rights they have; if we don’t end the presence of Israeli soldiers perpetually within the West Bank, then there will be an increasing feeling that if we cannot get peace with a leadership that is committed to non-violence, you may wind up with leadership that is committed to violence.”

He later elaborated, expressing apparently growing dismay over continued Israeli settlement expansion: “How, if you say you’re working for peace and you want peace, and a Palestine that is a whole Palestine that belongs to the people who live there, how can you say we’re planning to build in a place that will eventually be Palestine? So it sends a message that perhaps you’re not really serious.” That was a critique that will have resonated widely among those many Israelis, and critics from outside, who have long argued that Israel should limit any settlement building to areas it envisages seeking to retain in a permanent accord.

Kerry seemed to place the blame for the failure to make rapid and major progress in negotiations overwhelmingly on Israel, with no acknowledgment — in his statements as broadcast Thursday — of two intifadas, relentless anti-Israel incitement in the Palestinian territories, the Hamas takeover of Gaza and the constant rocket fire from the Strip. (It is important to note that Channel 2 aired only part of the full interview on Thursday. More is set to air Friday evening.)

In lamenting the IDF’s presence in the West Bank, Kerry positioned himself directly opposite Netanyahu, for whom an ongoing Israeli security presence in the Jordan Valley is a stated crucial condition for an agreement. Perhaps more surprisingly, he showed no evident concern over the danger of a Hamas takeover in the West Bank were the IDF to withdraw, disregarding a widely held concern — borne of the rapid ease with which Hamas swept Abbas’s forces aside in Gaza in 2007 — that the official Palestinian Authority forces alone would not be able to hold sway.

His comments, which indicated an assessment that Israelis are unrealistic about where the region is heading, seemed particularly bitter. “The alternative to getting back to the talks is the potential of chaos. I mean, does Israel want a Third Intifada?” Kerry asked rhetorically, before lashing out at ordinary Israelis. “I know there are people who have grown used to this,” he said, referring to the current relatively peaceful stalemate. “And particularly in Israel. Israel says, ‘Oh, we feel safe today. We have the wall, we’re not in a day-to-day conflict, we’re doing pretty well economically.’

“Well, I’ve got news for you,” he said, apparently addressing the Israeli public. “Today’s status quo will not be tomorrow’s or next year’s. Because if we don’t resolve this issue, the Arab world, the Palestinians, neighbors, others, are going to begin again to push in a different way.”

That line of thinking reflects much international conventional wisdom on the Israeli-Palestinian conflict — the assumption that Israel could attain peace with the Palestinians if only it wanted to, but that it just doesn’t want to enough. Many Israelis, Netanyahu most certainly among them, would counter that Israel cannot impose terms on a Palestinian leadership that, among numerous other problematic negotiating positions, still demands a “right of return” that would constitute suicide for the Jewish state. Many Israelis, their prime minister among them, too, would note that Israel is only too aware of how easily the relative calm could deteriorate, and thus are wary of relinquishing territory to a Palestinian leadership that, relatively moderate though it may be, might not be in a position to retain power and honor any accord amid sweeping regional instability.

For Netanyahu, watching Kerry’s from-the-heart interview must have topped what was already a pretty lousy day. In Geneva, the six world powers were inching toward a deal with the Iranians that the prime minister fears would leave Tehran with an enrichment capability even as the sanctions are eased — something Netanyahu considers a “historic error.”

Kerry weighed in on that, too, in the interview. Ultimately, if Iran doesn’t “meet the standards of the international community,” said the secretary unhappily, “there may be no option but the military option.” But, he quickly insisted, “we hope to avoid that.”

Just the sort of message Netanyahu has been urging the US not to deliver to Tehran.