The crisis touched off by last week’s announcement of Israel’s plans to build 1,600 new homes for Jews in Arab East Jerusalem during a high-profile visit by U.S. Vice President Joseph Biden appears to be escalating rapidly.

Michael Oren, Israel’s ambassador to Washington and a historian who has written widely on ties between the two nations, called the growing contretemps "the worst [bilateral] crisis in 35 years" in a teleconference with other U.S.-based Israeli diplomats Saturday night, according to a number of published accounts.

Twenty-four hours later, the powerful American Israel Public Affairs Committee (AIPAC), which advertises itself as "the most influential foreign policy lobbying organization on Capitol Hill," issued a statement declaring the administration’s condemnations of Israel’s behavior "a matter of serious concern."

"The administration should make a conscious effort to move away from public demands and unilateral deadlines directed at Israel," warned the group, which issued its statement shortly before 9:00 Sunday night. The timing served to underline the sense of alarm that has taken hold among supporters of the government of Israeli Prime Minister Binyamin Netanyahu.

Netanyahu, along with Secretary of State Hillary Clinton, is expected to keynote AIPAC’s annual meeting next weekend.

Other voices of the so-called Israel Lobby issued their own broadsides.

The neoconservative editorial board of the Wall Street Journal accused President Barack Obama of having deliberately "chosen this occasion to spark a full-blown diplomatic crisis with its most reliable Middle Eastern ally." It also warned that Israel will be more likely to attack Iran unilaterally if it "senses that the administration is looking for any pretext to blow up relations."

At the same time, the Israel Project mobilized its membership to write Congress and media demanding that the administration, in the words of one letter received by IPS, "BACK OFF!!!" Christian Zionists, including former presidential Republican presidential candidate Gary Bauer, also joined the fray.

But the Obama administration appeared determined to stand its ground Monday, as State Department spokesman P.J. Crowley told reporters that Washington is waiting for a "formal response by the Israeli government" to "specific" requests made by Clinton to Prime Minister Binyamin Netanyahu during what all parties described as a tense, 45-minute phone call reportedly made at Obama’s direction Friday afternoon.

While Washington has not yet commented on what those requests are, the Israeli newspaper Ha’aretz said they included reversing the East Jerusalem announcement; offering a major gesture to the Palestinians, such as a prisoner release; and agreement to peace talks that include final-status issues, including the fate of Palestinian refugees and East Jerusalem, as well as borders.

While Crowley insisted that Obama’s special envoy for Israeli-Palestinian peace, former Sen. George Mitchell, still intended to fly to the region this week to launch U.S.-mediated "proximity talks" on which both parties had agreed two weeks ago, he refused to set a specific date, describing the current situation as "fluid."

For his part, Prime Minister Binyamin Netanyahu, who apologized to Biden  and reportedly to Clinton, too, in their Friday conversation  for the timing of the East Jerusalem announcement but not for the actual building plans themselves, appeared unrepentant during a meeting of his right-wing Likud Party MPs Monday.

"Building in Jerusalem and in all other places will continue in the same way that has been accepted in the last 42 years," he said, in a reference to Israel’s "annexation"  never recognized by the U.S. or any other major power  of East Jerusalem after the 1967 Arab-Israeli War.

While the ongoing public crisis was clearly sparked by the coincidence of Biden’s visit and the East Jerusalem housing announcement  almost universally described by the mainstream U.S. media as a "slap in the face" at the vice president and by extension at Obama himself  its seriousness appears to be rooted in what Biden told Netanyahu and other top Israeli officials in private.

According to an account in Israel’s mass-circulation Yediot Ahronoth newspaper, Biden "warned his Israeli hosts that since many people in the Muslim world perceived a connection between Israel’s actions and U.S. policy, any decision about construction that undermines Palestinian rights in East Jerusalem could have an impact on the personal safety of American troops fighting against Islamic terrorism."

"This is starting to get dangerous for us," Biden reportedly said. "What you’re doing here undermines the security of our troops who are fighting in Iraq, Afghanistan, and Pakistan. That endangers us and it endangers regional peace.’"

In an important elaboration on these remarks posted on the ForeignPolicy.com Web site Saturday, Mark Perry, a writer with long-standing and close ties to the military brass, reported that Biden’s private comments reflected the collective view of top U.S. military commanders throughout the Middle East region.

They had been tasked in December by the chief of the U.S. Central Command (CENTCOM) to submit reports to him about the impact of Washington’s failure to make progress on Israeli-Palestinian peace on the perceptions of Arab leaders on U.S. standing and influence.

The result was a briefing presented to the chairman of the Joint Chiefs of Staff, Adm. Michael Mullen, in January and subsequently communicated to the White House that underlined the growing conviction in the region that "the U.S. was incapable of standing up to Israel, that CENTCOM’s mostly Arab constituency was losing faith in American promises, that Israeli intransigence on the Israeli-Palestinian conflict was jeopardizing U.S. standing in the region, and that Mitchell himself was ‘too old, too slow and too late.’"

A subsequent trip by Mullen to Israel  whose purpose was described in the media as designed to coordinate strategy on Iran  was aimed more at persuading the Israeli brass of the importance to the U.S. of achieving progress on peace talks, according to Perry.

But it became apparent with last week’s housing announcement that the message did not get through, according to Perry, so the administration responded first with Biden’s public condemnation, followed by Clinton’s phone call to Netanyahu, the summoning of Oren for what the ambassador described as an "extremely harsh" dressing down by Clinton’s deputy, James Steinberg, and now the demand for a "formal response" to her suggestions to Netanyahu.

"There are important and powerful lobbies in America: the NRA [National Rifle Association], the American Medical Association, the lawyers  and the Israeli lobby," wrote Perry. "But no lobby is as important, or as powerful as the U.S. military."

It is likely for this reason  rather than the more-superficial tiff over one settlement in East Jerusalem  that a plainly worried Oren told his colleagues that the current crisis is "very serious, and we are facing a very difficult period in relations," according to reports in the Israeli media.

The fact that Oren referred all the way back to 1975, when then-President Gerald Ford ordered a "reassessment" of relations with Israel in light of the latter’s rejection of U.S. proposals to move toward peace with Egypt, reinforced the growing conviction that the crisis is unlikely to be easily papered over in the absence of major concessions by Netanyahu.

At the time, Secretary of State Henry Kissinger defended the reassessment as necessary "in order to prevent an increasing radicalization in the area and an increasing tension and, above all, in order to avoid a war in which inevitably the United States would be involved at least indirectly, given the international circumstances."

(Inter Press Service)