In his controversial new book about Israel and the Palestinians, Jimmy Carter recounts his first visit to the Jewish state. It was a few months before the Yom Kippur War, he was the governor of Georgia, and his last stop was a visit with prime minister Golda Meir. "I said that I had long taught historical lessons from the Hebrew Scriptures," Carter writes, "and that a common historical pattern was that Israel was punished whenever the leaders turned away from devout worship of God." That belief system, Carter adds a few pages later, includes "being dedicated to the Judeo-Christian principles of peace and justice," living "in harmony with all their neighbors." It may strike Jewish readers as curious, to put it mildly, that a born-again Southern Baptist, a Sunday school teacher in his little Georgia town, would take such a proprietary tone in telling Golda Meir how to be a better Jew. Yet the exchange reveals something essential about Carter's book, something that has largely been missed in the firestorm around it: how its view of the Israeli-Palestinian conflict fits into the Christian debate. Understandably, American and Israeli Jews have analyzed and rebuked Carter's book from a Jewish perspective. The former president issued a deliberate, calculated provocation when he titled the slender volume Palestine: Peace Not Apartheid. His invocation of the word created for South Africa's officially racist doctrine was "a way of undermining the moral basis for Israel's existence," as Steven Bayme, director of the American Jewish Committee's Koppelman Institute of American-Israeli Relations, wrote. With such a title and such a metaphor, nobody should be very surprised that Jewish scholars and political leaders then dove in to Carter's text and even the book's maps to cite factual errors and challenge his interpretations. Fourteen members of an advisory board to the Carter Center have resigned, as has one of the center's fellows and a longtime Carter associate, Kenneth Stein of Emory University. But as all these events have swirled around, and as the book itself has climbed the best-seller list, an entirely different context for it has gone unnoticed. Israel has become one of the defining issues within American Protestantism, one of the markers in the struggle for supremacy between the politically and theologically liberal Mainstream denominations and their conservative foes in the faith's evangelical wing. For American or Israeli Jews unfamiliar with the turmoil among Protestants, a useful, if imperfect analogy, might be to think of Mainstream sects (Presbyterian, Episcopalian, United Methodist, among others) as the Reform Jews and the evangelical ones (Pentecostal and Southern Baptist, among others) as the Orthodox Jews. That is, for decades the Mainstream Protestants in the United States, like the Reform Jews here, were the most prosperous and most influential segment of the faith, the one surfing the wave of modernity. The evangelicals, like the Orthodox, were poorer and weaker, presumed to be bound for the dustbin of history. EXCEPT THAT such conventional wisdom proved wrong. In an era of religious revival in America, the Mainstream denominations have lost much of their vigor and, to put it in business terms, market share. The evangelicals, meanwhile, have both literally and figuratively capitalized on suburbanization in the Sun Belt, and the Religious Right has become the dominant faction of the Republican Party. With activism on Darfur and global warming, some evangelical congregations and leaders are even challenging the Mainstream's longtime franchise of social-justice issues. Like abortion rights, gay rights, the death penalty, school vouchers and stem-cell research - all domestic issues - Israel has served as a breaking point between the Protestant Left and the Protestant Right. And while Carter is personally a Southern Baptist, his stand on all those topics, now including Israel, places him firmly on the liberal flank of his faith. Randall Balmer, a professor of American religious history at Barnard College in New York, said that evangelicals view the Israeli-Palestinian conflict through the lens of Zionism while Mainstream Protestants view it through the lens of human rights. I would add that evangelicals view it through the prism of the Cold War confrontation while Mainstream Protestants view it through the prism of international diplomacy. In practical terms, these irreconcilable interpretations mean that there is simultaneously a boom in Christian Zionism among evangelicals and a boom in divestment activism among Mainstream Protestants, with the Presbyterians, United Methodists and United Church of Christ all recently considering various forms of economic pressure on Israel. As president, and even more so since his presidency, Jimmy Carter has been both moral and moralistic, both idealistic and preachy. One major reason his book has so stung American and Israeli Jews is that Carter's emphasis on dialogue and reconciliation delivered the Camp David peace agreement with Egypt. He is not Stephen Walt and John Mearsheimer, bloodless "pragmatists" willing to trot out Jewish-conspiracy theories to advance their preferred foreign policy. The scolding, holier-than-thou Carter, the one who took it upon himself to instruct Golda Meir in Old Testament theology, is the one who has plainly decided Israel bears the preponderance of blame for the violent gridlock in the Middle East. But in saying so, we Jews ought to realize, he's not only addressing us, or the foreign-policy establishment in Washington, or the Western Europeans, or the Arabs. He's preaching to the very divided choir that is the American Protestant population. At one level, of course, the volatile stand-off between Israel and the Palestinians is a world-class issue because the region is a world-class powder-keg. At another level, though, it's a bitterly contested frontier in a fight that's all about Christians. The writer, a professor of journalism at Columbia University, is a frequent contributor to The Jerusalem Post. Full disclosure: He has the same book editor as Jimmy Carter, but has never met or even spoken to the former president.