The knock at the door of her hotel room on Friday halts the conversation for a moment. No big deal, just to check whether Samantha Power drank from the minibar. Is she that troubled? Power responds with a brief laugh. The minibar remains sealed. That does not mean that the attacks do not bother her. In the course of the 50-minute conversation she leaves no stone unturned.

Knowing precisely what was written about her, what was quoted, she tries to refute, explain. Most of the things that were written are "misleading," she states. They are "a mark of desperation" on the part of those who do not want Senator Barack Obama as America's next president, "And fear that is where he is now headed."

The attacks on Obama in connection with Israel come in waves. There was the Zbigniew Brzezinski wave, against the former adviser to Jimmy Carter and current Obama supporter. Then came the Rob Malley wave, against the former adviser to Bill Clinton and current Obama supporter. Now the name of the game is Samantha Power. Not that the others have been forgotten; they'll be back, but you need a little variety. And Power, in contrast to Brzezinski and Malley, plays a key role in Obama's campaign. As one of his closest advisers, she is a far more significant target.

She knows it's not personal: "They attack me to hurt Barack," she says, referring to the candidate by his first name, as she will do throughout the interview. She's not showing off; they really are close. Malley doesn't speak with Obama in person. Power has many hours of conversation with him.

She came to New York to launch her book, fresh off the press, about Sergio Vieira de Mello, a Brazilian diplomat with the United Nations who spent years tackling various humanitarian crises, until he was killed in Iraq in 2003. She opens the conversation with a reference to this book, which her critics now quote. De Mello was in Lebanon in 1982 when Israel started the Lebanon War, and didn't like what he saw. She quotes him, among other things, calling the Israelis "bastards." She says the book depicts its subject's thoughts, not her own. But "the book is now used to attack me." For example, because of the following paragraph: "The Security Council were not prepared to deal with the gnarly issues that had sparked the Israelis' invasion in the first place: dispossessed Palestinians and Israeli insecurity."

Power would like to go through like this, item by item, and repel every attack. There isn't enough space to cover all of these attacks, and all the defenses. In recent weeks, a young and talented writer named Noah Pollack, who writes for the right-wing magazine Commentary, has delved deeply into Power's statements on record. Among other things, he found the following things she said, in a 2002 interview, about what should be done to stop the Israeli-Palestinian conflict: "[It will] mean sacrificing - or investing, I think, more than sacrificing - billions of dollars, not in servicing Israel's military, but actually investing in the new state of Palestine, in investing the billions of dollars it would probably take, also, to support what will have to be a mammoth protection force, not of the old Rwanda kind, but a meaningful military presence."

In that same interview, Power said that the situation will "require external intervention." Pollack very reasonably interpreted this as an expression of support for a "ground invasion of Israel and the Palestinian territories." Otherwise, he wrote, what did she mean when she spoke of "a mammoth protection force"?

Power herself recognizes that the statement is problematic. "Even I don't understand it," she says. And also: "This makes no sense to me." And furthermore: "The quote seems so weird." She thinks that she made this statement in the context of discussing the deployment of international peacekeepers. But this was a very long time ago, circumstances were different, and it's hard for her to reconstruct exactly what she meant. Anyway, what she she said five years ago is less important that what she wants to say now: She absolutely does not believe in "imposing a settlement." Israelis and Arabs "will negotiate their own peace."

In any case, she stresses, this is not exactly her field. Power is the Anna Lindh Professor of Practice of Global Leadership and Public Policy at Harvard University's Kennedy School of Government. Her reputation stems largely from her excellent previous book, "A Problem from Hell," which documents the world's indifference to genocide, from the Armenians to Rwandans. It earned her a Pulitzer Prize and made her an extremely popular speaker among Jewish communities in America, which are very active in areas that are her bread and butter, such as stopping the killing in Darfur, Sudan.

Power is somewhat frustrated by the need to address every snippet of past statements. After all, the candidate himself, Obama, has expressed clear positions on nearly every matter relating to the Middle East. Like others among Obama's supporters and campaign staff, she thinks that a problem with Obama's critics is that they tend to ignore completely what he himself says. As though his words are merely of secondary importance, and what reflects his true opinion are all sorts of past quotes from close and not-so-close aides.

But the truth is that critics have also turned the spotlight on current quotes from Power, for instance from a recent column she wrote for Time Magazine, in which she complains that "the Bush Administration attempts to gin up international outrage by making a claim of imminent danger, only to be met with international eye rolling when the claim is disproved." Once again Power's critics maintained: She believes that Iran is not dangerous, and accepts as fact the pathetic National Intelligence Estimate.

But she doesn't understand what all the fuss is about: She doesn't claim that the NIE is correct, but rather that the international community is using it to fend off Bush on the Iranian issue. And lest there be any doubt: "I do not underestimate the threat that is Iran." Her objective - Obama's objective - is "to neutralize Iran."

Iran is one of the items troubling Israel supporters who scrutinize Obama's positions. The former Israeli ambassador to Washington, Danny Ayalon, demanded that the candidate explain what he means to gain by meeting Iran's president, Mahmoud Ahmadinejad. Power volunteers to do so. "Do people have the right to be worried? Of course," she says. Just so long as they portray accurately what we say.

With regard to Iran: "Reasonable people can agree or disagree on the issue of meeting with Ahmadinejad," but here's what she thinks: The chance of persuading Ahmadinejad may not be great, but it is worth examining, and a meeting "will increase the chance for mobilizing international sanctions, because the world will be reminded that Ahmadinejad is the problem," not America as many now believe.

And it's fine by her that not everyone agrees with that approach, but she is not willing to put up with distortion of her positions, or those of the candidate. Mainly, she says, she finds "sickening the claims that raise the suspicion that there is some anti-Semitic undertones to our views."

In the interest of brevity, here, in a nutshell, are several more of Power's positions: Immediate and intensified involvement in the Israeli-Palestinian peace process. It has to be resolved first of all for the benefit of the parties involved, but also to preevent "cynical Arab leaders" from exploiting the conflict as a tool for justifying their policies.

She thinks that the talks between Prime Minister Ehud Olmert and Palestinian President Mahmoud Abbas are being held "in good faith."

Asked who is to blame for there being no agreement yet, Power says there is no point expanding on that, but emphasizes that "I've never blamed Israel for the failed talks" (at Camp David). But precisely how should these talks be handled, and what should the goal be? She's no expert on that, she says, and suggests calling Dan (Shapiro), the campaign's adviser on the Middle East, or Dennis (Ross), who also advises Obama (advises - but is not an adviser).