On Monday night, the heads of two major pro-Israel organizations and the editors of two publications associated with support for Israel gathered for a relatively routine event: a panel discussion at the 92nd Street Y, in New York, on "what it means to be pro-Israel." A few hours earlier, members of the American Studies Association, an association of some 5,000 American studies college professors, had voted 2 to 1 to boycott Israeli universities. Shortly after the panel moderator and editor-in-chief of the Jewish Daily Forward, Jane Eisner, raised the issue, the panel broke up in a relatively spectacular walk-off.

"I was stunned by what I can only describe as a temper tantrum," Eisner wrote later that night on the Forward's Web site, describing the heated behavior of John Podhoretz, who edits the right-leaning publication Commentary. Podhoretz stormed off the stage after arguing with one of the other two other panelists, Jeremy Ben-Ami of the left-leaning advocacy group J Street. Third panelist David Harris, of the more centrist American Jewish Committee, wisely kept out of it.*

"It is hard not to view this lopsided scene as an incredibly sad commentary on the difficulty of engaging Jews with vastly different views on Israel in civil dialogue," Eisner wrote. There was something so remarkably, painfully sensitive about the American Studies boycott that a group of people whose jobs entail regularly arguing about Israel, and who by and large agreed on the issue, were brought near the point of blows. The incident is perhaps a sign of the degree to which the boycott touches on deeper issues that are often left unstated -- not so much divides within pro-Israel movements as unanswered, or unanswerable, questions about a U.S. Israel-supporter's responsibility toward and relationship with Israel.

The controversy was not over the boycott itself, or the merits of the "BDS Movement," which advocates boycotts, divestment and sanctions to change the Israeli government's behavior with regard to the Israeli-Palestinian conflict. The most telling fact of this incident is that all four people on stage agreed about the issue at hand: that BDS campaigns such as the academic boycott are harmful and counterproductive. But if they agreed, why did they argue so vehemently that one of the participants marched off mid-event?

The four people on stage represented the left, right, center and mainstream of Jewish American thought about Israel. They would all, I presume, identify as Zionist, which is to say they are "pro-Israel" to the extent that they support the existence of a Jewish state in the ancestral homeland. But they would likely offer very different definitions of the key words in that sentence: "Zionist," "pro-Israel," "support." And therein lie the seeds of this and many other perhaps intractable disagreements about Israel.

In debates about Israel, disagreements that might seem minor on the surface – the "tyranny of small differences," as one Israel-watcher put it to me – are often something much graver. If you know what to watch for, you can observe somber, serious people like these four panelists talk around underlying issues so sensitive they are rarely addressed or even acknowledged. Issues that are almost always below the surface, but too deep to come out except in moments of the most heated candor, often surprising even the people naming them.

These are questions so difficult, and that cut so close to the core of what it means to be an American supporter of Israel, that even scholars or professionals with decades invested in Israeli issues will hesitate to touch them. But you can hear them, if only hinted at, in arguments like Monday evening's. Is it good or bad for Israel that more American Jews are questioning Israeli policies? At what point, if ever, should one's support for Israel be limited by the needs of non-Israelis touched by the conflict? Is a Zionist's responsibility to guard Israel's survival, to guard Israel's interests or merely to concern oneself dispassionately with the issues facing the country?

Is Israel today best viewed in the context of post-1973, after which it has enjoyed vast military superiority over its neighbors and the undivided support of the United States? Is the most relevant context the decades of war against neighboring countries that actively sought Israel's destruction? Or should Israel's place in the world be considered more in light of the Holocaust and, perhaps, the danger that it could happen again?

Are Israeli security policies in the Palestinian territories a response to Palestinian terrorism, or is it the other way around? If some policies go too far, what level of responsibility does an American Zionist or the United States itself have to curb them? How does an American Jew balance the sometimes-competing interests of Israel, the United States and Palestinians?

Are Jews in Israel beyond still, as the New Republic's Marc Tracy put it, "a community under threat," as has "historically been the default mode of the Jewish people"? (Tracy says no, but posits that Podhoretz would answer yes.)

Some of these questions are simply unanswerable. Some are trick questions. Some are highly taboo; the question about competing interests can easily echo accusations, made by the most anti-Semitic movements in history, that Jews harbor "dual loyalties" and cannot be trusted. But many are just extremely difficult, touching on issues of identity, politics and personal responsibility. They cause conflict both because no one can agree on the answers, or often even the terms of the questions themselves, and because everyone ends up judging one another according to their own personal and widely varying standards.

That's how four pro-Israel Americans can agree that the American Studies boycott is "hypocritical and ultimately counterproductive," as Eisner put it, but still find themselves divided by it. The boycott is largely symbolic and unlikely to have much real impact; it's a political act, which doesn't make it necessarily wrong, although it is certainly outside the mainstream of American thought about the Israel-Palestine conflict. But that symbolism, intentionally or not, touches on some of the toughest questions about what it means to be an American concerned with Israel.

It is often said that a major hurdle to Israel-Palestinian peace is that partisans of the two sides simply live in different worlds with different sets of facts. But at least they can say as much out loud. In internal pro-Israel debates, to even acknowledge that fact would often be too much; no one wants to undermine the sense of common purpose. If the American Studies Association boycott does nothing else, it is likely to continue forcing those quiet disagreements to the surface, as it did  Monday evening.

* – Correction: This sentence originally indicated that Podhoretz argued with Ben-Ami and Harris before leaving the stage. In fact, Harris did not engage in the argument, according to Eisner and a journalist in the audience.