In the early 1980s, as a young community organizer in Chicago's projects, Barack Obama had had enough of Louis Farrakhan's acolytes, black separatists who were increasingly anti-Semitic. "Notions of purity of race or of culture," Obama wrote in his 1995 memoir, "could not bring self-esteem" to typical blacks any more than they could to him, the son of a white mother, and longed-for African father. "Our sense of wholeness would have to arise from something more fine than the bloodlines we'd inherited."

You might think that Obama - natural cosmopolitan, editor of the Harvard Law Review, reader of Philip Roth - would be the kind of leader American Jews would flock to. Who if not Jews have benefited from the ideal of "integration" that made Obama's candidacy possible? And, indeed, at least 60 percent of American Jews (and a much higher proportion of young Jews) already say they'll be voting for him.

But Israeli elites have remained resistant, even condescending, and these attitudes have reinforced those of older American Jews, especially in Florida, which Obama needs to carry. Blogs circulated by Israeli rightists claim that he has had a "disturbing pattern of associations" - for example, with Columbia University's Rashid Khalidi, whose big sin, apparently, is his own pattern of association with the very Palestinian Authority leadership Israel's centrist government considers a negotiating partner.

Yet even my centrist friends in Israel, young and old, smart and smarter, seem edgy about Obama. ("America is not ready," they say.) Veteran columnists charge Obama with both naivete and - without seeing the contradiction - Machiavellianism. One of Channel One's new TV news anchors, whose Tel Aviv pals probably think Jim Crow is the name of a bourbon, pounced on him for misremembering which concentration camp his uncle helped liberate. As if the deep impression made on a sensitive youth by his uncle's postwar shock is not the point.

What's the problem? Perhaps there is something about Obama's hybridized identity that does not quite fit the social logic Israelis think vaguely consistent with Zionism. Who, if not we Israelis, are still anxious about whether our nationalism entails "purity of culture" or "bloodlines"? If democratic standards can make a black man a mainstream American, can it not also make an Arab a mainstream Israeli? To what "demographic" does Obama belong?

Israelis instinctively fear charismatic leaders who can whip up huge audiences, especially leaders who seem sincere about Christian grace, without being pro-settler evangelicals. Will Obama, so the argument goes, be another Jimmy Carter - you know, another peacemaker out of his depth? The fact that Carter actually achieved a peace treaty, indeed, risked his presidency to force Anwar Sadat to agree to the deal without a settlement freeze by Israel, is beside the point. Israelis are allowed to condemn settlements. An American who does is not "a friend."

There is probably a buried fear, in this context, that Israel's special pleading - about how non-Jews have no right to judge Israel's conduct of the occupation - may not quite work on Obama, just as it did not work on Dr. Kissinger. Like liberal Israelis who cringe when they hear Avigdor Lieberman justify land grabs by citing "Jewish history," Obama has heard apologetics for victim exceptionalism from sly black pols like Al Sharpton since his youth. You can't just tell him - how did Prof. Yehezkel Dror put it? - that "morality must be subordinated to survival." It takes one to know one.

The most obvious problem with Obama, however, is more immediate. He has had the brass to insist on persistent diplomacy, not military action, against Iran. He would not utterly renounce the use of force, he told AIPAC in measured, unapologetic language last week, but he would first rebuild America's alliances and meet with Iranian officials. He would offer to ease sanctions and work to end Iran's comparative commercial isolation - if in return Iran ended its nuclear program.

My friends in the center are not persuaded. Many, it seems, would like to see a strike against Iran's nuclear facilities before President George W. Bush leaves office - or they think they might - or want a new president who at least entertains the idea. They think (rashly, I believe) that a strike can be something relatively clean and decisive, like the one against Iraq in 1981 or Syria last year. They've applauded Bush for invoking the lessons of Munich, even if he has learned his history from PowerPoint. Anyway, if there are greater complexities in the region - honor cultures, rival Islamic theologies, pro-American sentiment in the Tehran bazaar, etc. - Israeli elites want to be the ones to tell Washington what to think about them. They don't want to be told.

Obama, in other words, represents a change Israelis are not sure we know how to live with after 40 years of talk about our strategic military alliance. He symbolizes America's great power to attract, as opposed to its degraded power to deter. Indeed, he wants to be the face of global integration, from Rio to Jakarta - ironically, the very integration Israeli entrepreneurs excel at. John McCain says he will be the jihadists' worst nightmare. Obama reminds us that the war McCain helped launch has been their dream come true.

Obama's AIPAC speech was, in this sense, a masterful gesture toward the future, and he richly deserved his standing ovation. He reassured his audience about Israel's security, but emphasized collective security. He promised Israel support for its capital in an "undivided" Jerusalem, without barbed wire and walls, but did not promise the Likud a "united" Jerusalem. Most important, he promised not to neglect the peace process until his last year in office.

For Israelis, this last promise may well provoke the saddest fear of all. It is the fear of hoping again.

Bernard Avishai is the author, most recently, of "The Hebrew Republic" (Harcourt). He blogs at www.bernardavishai.com.