Since its creation more than six decades ago, the state of Israel has been at times a vexing ally to the United States.
But it poses a special challenge for President Obama, whose foreign policy emphasizes the importance of international rules and organizations that successive Israeli governments have clashed with and often ignored.
His dilemma has come into clear focus after Israel's military operation this week, in which commandos boarded a Gaza-bound aid flotilla in international waters, killing nine civilians, among them a 19-year-old U.S. citizen of Turkish descent.
The head of Israel's foreign intelligence service warned parliament the next day that the country is "gradually turning from an asset of the United States to a burden." An Irish aid ship was steaming toward Gaza on Friday night despite Israeli warnings that it would be stopped.
Israel 'is a problem'
Israel has a unique set of security threats and national ambitions that have fostered policies inconsistent with Obama's broader agenda, including his push to stop the spread of nuclear weapons and repair U.S. relations with the Islamic world.
That has forced him to carve out exceptions for Israel that undermine the consistency he seeks in dealing with allies and antagonists alike.
Those differences have also made it hard for Obama to speak unequivocally in support of Israel during difficult times. Asked by CNN's Larry King on Thursday if it were "premature then to condemn Israel," Obama said, "I think that we need to know what all of the facts are."
Israeli officials "look at the world quite differently from the way from this president does, and they are not willing to just fall in line because he is the president," said Daniel C. Kurtzer, a former U.S. ambassador to Israel who advised Obama's campaign and now teaches at Princeton University. "Israel and the United States are seeing the threat environment in the region — and the ways to deal with the threat environment — in increasingly different ways. And for the United States that means Israel is a problem, as an ally heading in a very different direction."
So far, Obama has little tangible to show for his Middle East policy; the raid threatens to undercut what progress he has made. His attempt to turn "proximity talks" between Israelis and Palestinians into direct negotiations has been complicated by the Gaza operation. So has his bid for new sanctions against Iran at the United Nations.
Patch up relations
Before the raid, the administration was working to patch up relations with Israeli Prime Minister Binyamin Netanyahu, which frayed this year over Israel's settlement policy, and with an American Jewish community that has long viewed Obama as an uncertain friend of Israel.
Last week, Obama marked Jewish American Heritage Month with a White House reception for 200 guests, who encountered at the entrance President Harry Truman's May 1948 statement recognizing the state of Israel.
Obama also met last month with three dozen Jewish members of Congress, telling them, according to one participant, that he "can't impose" a peace settlement on Israelis and Palestinians but "may outline a solution for the parties."
To Israel and its supporters, though, Obama must show an emotional understanding of the threats they face before pushing peace proposals.
Israeli leaders have traditionally found few places besides the United States to turn to for support. Israel mistrusts international organizations such as the United Nations, whose General Assembly once passed a resolution equating Zionism with racism. It was later reversed.
David Makovsky, a fellow at the Washington Institute for Near East Policy, said that "both Bill Clinton and [George W.] Bush were able to evince a visceral identification with an Israel that exists in a very difficult neighborhood." That identification, he said, was essential to good relations with the Israeli government and public, which has a low opinion of Obama.
"Obama has been more detached and programmatic in his approach," said Makovsky, who wrote the 2009 book "Myths, Illusions, and Peace: Finding a New Direction in the Middle East" with Dennis Ross, an Obama adviser on the region. "But there's a paradox in this because you need a shared agenda to have trust. And you need trust to forge a shared agenda."
In his June 2009 address to the Muslim world at Cairo University, Obama drew applause for stating that "the United States does not accept the legitimacy of continued Israeli settlements" in territories Israel occupied in the 1967 war. He said that "this construction violates previous agreements and undermines efforts to achieve peace."
Those remarks represented a sharp turn from the Bush administration's position that Israel could expect to keep its largest West Bank settlement blocs.
"The key to understanding this president is to know that he is about change — it wasn't just a slogan," said Michael B. Oren, Israel's ambassador to Washington. "This is a changing relationship, but change doesn't necessarily mean friction."
Israeli leaders have argued that Jewish settlements in the West Bank serve as a buffer against Arab attack from the east. But many members of Netanyahu's Likud party also believe Jews have a biblical claim to the land, making it politically difficult for the prime minister to stop settlement construction.
"We have areas of disagreement — Jerusalem is one, and the friction around the settlements," said Oren, who spent four hours at the White House this week meeting with senior administration officials. "They want us to be more flexible on the Gaza issue, and we also want to change the status quo. The fact we are having this dialogue is a sign of our shared interests."
Double standards
But Obama, who has sought to eliminate double standards in U.S. foreign policy since taking office, has had to make exceptions for Israel on some of his most important initiatives.
At the end of the Nuclear Security Summit he convened in April, Obama spoke at length about Iran's need to meet its obligations under the Non-Proliferation Treaty or face harsher sanctions for not doing so.
Asked if he would press Israel to declare its decades-old nuclear program and sign the Non-Proliferation Treaty, which moments earlier he had called "the cornerstone of our global efforts to prevent the spread of nuclear weapons," Obama said, "I'm not going to comment on their program."
"What I'm going to point to is the fact that consistently we have urged all countries to become members of the NPT," he added.
A major treaty review last month ended with a statement that singled out Israel's nuclear program for criticism, but did not condemn Iran's secret nuclear facilities. James L. Jones, Obama's national security adviser, called the omission "deplorable."
"This administration faces two very difficult stances to reconcile," said Robert Malley, a former Middle East adviser to Clinton. "You have Israel feeling that it stands apart because it faces challenges unlike anyone else. And you have an administration that wants to establish a rule-bound international order. The question is how effectively do they juggle the two, and the test of that will be whether they achieve their policy."
Staff writer Glenn Kessler contributed to this report.