The impending arrival of Israel's prime minister, Benjamin Netanyahu, will start an unpredictable engagement by President Barack Obama in trying to shift the Middle East from a tense standoff to Arab-Israeli peacemaking.
Netanyahu, due at the White House on May 18, has signaled he intends to resist a key plank in Obama's program: a Palestinian state carved out of land Israel has held since winning the 1967 Mideast War with the Arabs.
New to Middle East peace efforts, Obama is expected to insist on a "two-state solution" and try to entice Netanyahu and other skeptical Israelis with pledges of security assistance.
It is the president's first attempt at solving a dispute that has shadowed American presidents for more than 60 years. Obama is moving into the dispute with characteristic energy. But he acknowledged as a presidential candidate that "it's unrealistic to expect that a U.S. president alone can suddenly snap his fingers and bring about peace in this region."
The case for Palestinian statehood will be made later in May during visits by Palestinian leader Mahmoud Abbas and Egyptian President Hosni Mubarak, whose country has been at peace with Israel since 1979.
Mubarak is expected on May 26, said a State Department official speaking on condition of anonymity because the date of the visit has not been announced. Officials said Abbas is due to visit as well, but the date has not been finalized.
Netanyahu is likely to try to take the initiative with proposals to improve economic conditions for the Palestinians, many of whom are locked in poverty, and by welcoming unconditional negotiations without a stated goal of Palestinian statehood.
Vice President Joe Biden, in a speech to the pro-Israel lobby American Israel Public Affairs Committee, indicated that approach would not suffice.
"Israel has to work toward a two-state solution," Biden told AIPAC last week. And, Biden said, Israel should not build more settlements and should dismantle existing outposts and allow Palestinians freedom of movement on the West Bank.
Abbas, for his part, is due to insist on a state, and one that incorporates part of Jerusalem, while Mubarak might dust off Egypt's bid for a nuclear-free Middle East, which would mean Israel giving up its presumed nuclear arsenal.
So far, Israel would have none of this. But pressure could build in light of Obama's diplomatic efforts to keep Iran from developing nuclear weapons.
For most Israelis, Iran is the biggest threat to their existence, and Obama's overtures to Tehran tend to heighten their anxieties, especially in light of Iranian President Mahmoud Ahmadinejad's threat to see Israel erased from the map.
Last month, in congressional testimony, Secretary of State Hillary Rodham Clinton appeared to caution Israel that it "can't stay on the sidelines with respect to the Palestinians and the peace efforts" if it expects Arab governments to form a coalition to contain Iran.
Netanyahu is likely to seek Obama's assurance that Israel can defer to the United States any consideration of a military strike against Iran. At the same time, though, Israel is reserving its right to protect itself.
Foreign Minister Avigdor Lieberman has said the obstacle to a peace deal "is not Israel. It is not the Palestinians. It's the Iranians."
Iran's ruling regime is very unpopular with the Iranian people and will not survive long, a senior Israeli defense official, Brig. Gen. Michael Herzog, said Thursday. But it is not clear whether Iran will go nuclear before the end of Ahmadinejad's reign, Herzog cautioned.
Herzog, chief of staff to Israeli Defense Minister Ehud Barak, estimated that Iran would reach the "breakout point" in producing nuclear weapons by late 2010 or early 2011.
Herzog bluntly warned Tehran that "when we say a nuclear Iran is unacceptable, we mean it. When we say everything is on the table, we mean it."
Obama, like his predecessors, has not ruled out using nuclear weapons as Israel has threatened.
But Obama is putting new emphasis on direct diplomacy. Iran has shown some interest, all the while insisting its nuclear program is designed to develop energy.
Herzog said "we have no doubt" of Iran's objective and that the United States has the same intelligence.