WASHINGTON  - If the past week was any indication, the U.S.-Israeli relationship, which could scarcely have been smoother during the eight-year presidency of George W. Bush, appears headed for choppy waters.

Since taking office 10 days ago, the new government headed by Prime Minister Binyamin Netanyahu has been slapped down - at least, rhetorically - by the two most senior members of the Barack Obama administration, including the president himself.

Other steps taken by the administration in the past week, particularly its vow to participate fully in multilateral talks with Iran on its nuclear program "from now on", have bolstered the notion that Washington under Obama no longer sees eye to eye with the Jewish State, and especially its new right-wing leadership.

The latest developments come as the administration has given top priority to redressing the deteriorating situation in Afghanistan and Pakistan, increasingly referred to as "AfPak", as part of an ambitious strategy whose ultimate goal is to "disrupt, dismantle and defeat" al Qaeda. Planning for the new strategy was overseen by Bruce Riedel, a former top Central Intelligence Agency (CIA) analyst on Middle and South Asia, who has long insisted that resolving the conflict between Israel and the Palestinians would go a long way toward reducing al Qaeda's appeal throughout the region.

That appears to reflect the view of other key administration officials, including Obama himself who, despite the victory of Israeli parties opposed to a two-state solution and widespread skepticism that progress toward a peace accord is possible in the near term, has repeatedly stressed the urgency of that goal.

The first shot across the Netanyahu government's bow this week came in response to the maiden speech by his controversial new foreign minister, Avigdor Lieberman, in which he renounced Israel's commitment to the Annapolis Conference launched by the Bush administration in November 2007 to get Israeli and Palestinian negotiators to address "final status" issues for a two-state solution rather than become bogged down in satisfying pre-conditions required by the 2003 "Roadmap" for arriving at that stage.

"There is one document that binds us, and it is not the Annapolis Conference," declared Lieberman, whose extreme anti-Arab views have gained widespread notoriety here. "That has no validity."

As noted by the U.S.-based Jewish Telegraphic Agency (JTA), Obama's response "was swift and came from its highest reaches - the president himself."

"Let me be clear: the United States strongly supports the goal of two states, Israel and Palestine, living side by side in peace and security," Obama said in his address Monday to the Turkish parliament in Ankara. "That is a goal shared by Palestinians, Israelis, and people of goodwill around the world. That is the goal that the parties agreed to in the Road Map and at Annapolis. That is a goal that I will actively pursue as president of the United States."

Commentators noted it was the first explicit mention of Annapolis by Obama since his inauguration in January and was thus taken as a deliberate rebuke.

The second slap came a few days later in the wake of a widely noted interview of the new Israeli prime minister by The Atlantic magazine's Jeffrey Goldberg, entitled "Netanyahu to Obama: Stop Iran - Or I Will."

The interview re-iterated Netanyahu's and other Israeli officials' increasingly urgent threats to attack Tehran's nuclear facilities unilaterally, if Washington's diplomatic efforts to persuade Iran to abandon its nuclear program do not quickly bear fruit.

Asked by CNN anchor Wolf Blitzer whether the Obama administration was concerned about Netanyahu's threat, Vice President Joseph Biden, who appears to have emerged as one of Obama's main foreign policy advisers, cast doubt on its credibility. "I don't believe that Prime Minister Netanyahu would do that," said Biden, adding, "I think he would be ill-advised to do that."

Subsequent efforts both inside and outside the administration by individuals and lawmakers closely associated with the so-called "Israel Lobby" to persuade the White House to soften what appeared to be Biden's categorical rejection of unilateral Israeli action were unavailing, according to several sources.

"I've been given no reason to believe that the vice president wasn't speaking for the administration," said one government official who works on the Middle East and the Gulf but was not authorized to speak publicly on the matter. He noted that Biden's former top staffer on the region when he chaired the Senate Foreign Relations Committee, Puneet Talwar, is now the senior director for Iran, Iraq, and the Gulf on the National Security Council (NSC).

Indeed, it was Talwar, rather than the Secretary of State Hillary Clinton's more hawkish "Special Adviser" on Iran, Dennis Ross, who accompanied Undersecretary of State for Political Affairs William Burns to London this week to co-ordinate strategy for negotiating with Tehran on its nuclear program with their counterparts from Britain, France, Germany, Russia, and China (P5 + 1) as the administration's first major step toward full and direct engagement "on the basis of mutual respect and mutual interest" with Iran, as promised by Obama.

"Obama is trying to demonstrate his sincerity (toward Tehran), and the last thing he wants is for Netanyahu to undermine his efforts by militarizing the atmosphere," said Trita Parsi, the president of the National Iranian American Council (NIAC) and author of ‘Treacherous Alliance', a history published in 2007 of the trilateral relationship between Iran, Israel, and the United States.

But Netanyahu has other reasons to be concerned. Europe increasingly favors softening the Quartet's conditions for engaging Hamas, a notion that is anathema for Netanyahu but that is being given serious consideration by the Obama administration as part of what appears to be a major, if quiet, policy review.

That Obama decided to deliver his first major policy address toward the Islamic world in Turkey - whose dominant political figure, Prime Minister Recep Tayyip Erdogan, has not only championed Hamas, but also repeatedly accused Israel of war crimes during its recent Gaza campaign - was, to some observers, a provocative choice, even if it wasn't meant primarily as a signal to Israel. "The White House knew it was open to that interpretation," said Daniel Levy, a former Israeli peace negotiator with the New America Foundation.

It was, of course, Erdogan who also carried out a two-year mediation between Netanyahu's predecessor, Ehud Olmert, and Syria's Bashar al-Assad over the terms of a peace accord that included the return to Damascus of the Golan Heights. Despite Netanyahu's public opposition - he had privately explored the idea when he was prime minister in the late 1990s - to such a deal, many analysts believe Obama wants to pick up where Erdogan left off, in addition to pursuing engagement with Iran and prodding Netanyahu on the Palestinian front.

Indeed, unconfirmed reports that Obama's Special Representative for Middle East peace, former Sen. George Mitchell, may visit Damascus when he makes his third tour to the region next week suggest that the Syrian track could be another source of friction. Joining Mitchell's staff last week was Frederic Hof, a well-respected former senior diplomat, who recently published a highly detailed plan for the transfer of the Golan to Syria as part of a peace settlement.

The contretemps over both the Annapolis Conference and Israel's threats against Iran do not yet translate into a major clash between the new governments in both Washington and Tel Aviv - indeed, they may have served as "red herrings" designed to make Netanyahu look generous and more reasonable if he backs down on them later, according to Levy.

However, these initial skirmishes may nonetheless presage a stormy period between the two allies, one that could be touched off in the short term if Israel decides to follow through on plans to demolish several dozen Palestinian homes in East Jerusalem or engages in new settlement activity, moves that the Obama administration has made clear it will strongly oppose.