WASHINGTON (JTA) — Amid the dramatic shift in tone in the U.S.-Iran relationship following Iranian President Hassan Rouhani’s visit last week to the United Nations, Israeli officials are broadcasting a clear message: Be skeptical.

But at the J Street conference in Washington this week, which drew nearly 3,000 participants, including a slew of Israeli and U.S. analysts and politicians, the message was much different: Take Tehran at face value and give diplomacy a chance.

If Iran says it is ready to negotiate on its nuclear program, that may be proof that the strategy of sanctions coupled with diplomacy is succeeding, Kenneth Pollack, a senior fellow at the Brookings Institution, said at a panel discussion devoted to Iran.

“The whole point was to use a series of carrots and stick to try and get the Iranians to come around,” he said. “This is what victory looks like.”

But, Pollack cautioned, this may be only the start of a long process of negotiation.

“We’ve completed part of what we want to do,” Pollack said. “Perhaps this is the end of the beginning.”

J Street President Jeremy Ben-Ami sounded an optimistic note.

“To my mind this is wind in the sails,” he said of the phone call last Friday between President Obama and Rouhani. “The right solution to most of the problems that affect America in the Middle East is through diplomacy.”

The Israeli Knesset members who came to the conference were divided over whether Prime Minister Benjamin Netanyahu’s skeptical approach is the best way to respond to the diplomatic push by Iran.

“We are not party poopers because we don’t know if there is a reason for a party,” said Tzachi Hanegbi, a Likudnik and Netanyahu confidant. However, he described Iran’s diplomatic overtures as “the fulfillment of our dreams.”

Merav Michaeli, a Knesset member from Labor, said Netanyahu refuses to accept successful diplomacy with Iran because he wants to see Iran forfeit. She characterized the prime minister’s approach this way: “It’s not about reaching an agreement, it’s not about reaching the goal, sometimes we even forget along the way what the goal is — but we need to win.”

But, Michaeli said, “We need to realize it’s OK to negotiate. We don’t always have to win.” Embracing diplomacy doesn’t mean shelving the threat of a military strike, she said. “If they’re lying, we’ll find out and we can always use the other way.”

Though Iran took a backseat to discussion of the Israeli-Palestinian conflict at the J Street conference, the Obama-Rouhani phone call helped make it a major topic of debate at the confab.

Husam Zomlot, executive deputy commissioner of the Palestinians’ Fatah Commission for International Affairs, told JTA that Netanyahu’s skepticism toward Rouhani is driven by his fear that Iran might be removed as a useful political tool for Israel.

“I am so delighted at this phone call, and I hope this is going to bring an end to this use of Iran as a pretext or an excuse to not move ahead with the peace process,” Zomlot said.

Meir Javedanfar, a professor of contemporary Iranian politics at the Interdisciplinary Center in Herzliya, Israel, said that whatever the outcome of the Iranian situation, the Israeli-Palestinian conflict should remain a priority for Israel.

“Iranian nuclear program, no Iranian nuclear program — we still need to make peace with the Palestinians,” Javedanfar said “I think not making peace with the Palestinians will be as big an existential danger as Iran.”