WASHINGTON -- Neither President Barack Obama nor Israeli Prime Minister Benjamin Netanyahu mentioned Hasan Rouhani after their White House meeting Monday morning.
They didn't have to. The Iranian president, whom Mr. Netanyahu has labeled a "wolf in sheep's clothing," and whom Mr. Obama phoned last week in the first U.S.-Iranian leader-to-leader contact in 34 years, was the obvious, if unspoken, subject of the discussion.
Mr. Netanyahu said he was comforted to hear Mr. Obama declare that Iran's "conciliatory words have to be matched by real actions." The president said he would take no options off the table, including military action, to prevent Iran from obtaining a nuclear weapon.
It was a disciplined show of unity by two leaders who have clashed in the past over how to deal with the nuclear threat from Iran, and may soon face further strains as the United States tests the diplomatic overture Mr. Rouhani made last week at the United Nations.
Negotiators from Iran and six world powers, including the United States, are to meet Oct. 15 in Geneva to discuss how to curb the Iranian nuclear program. Iran, analysts say, will have to offer a much broader proposal if it expects relief from sanctions that have devastated its economy.
Analysts and former administration officials said the Tehran government hasn't yet come to grips with the scale of concessions they must make to obtain even modest relief from sanctions. Mr. Netanyahu has laid out a list of demands, including that Iran relinquish its right to enrich uranium, turn over its stockpile of enriched nuclear fuel, dismantle its Fordo nuclear facility and suspend construction of a heavy-water reactor at Arak.
Mr. Netanyahu is to address the U.N. General Assembly today. His visit with Mr. Obama beforehand amounted to a political gut-check after a week of dizzying diplomatic developments during Mr. Rouhani's New York City visit.
The Israeli government has clearly been rattled by the Iranian charm offensive, leaking word last week that Mr. Netanyahu, in his General Assembly speech, would liken Iran's diplomatic initiative to that of one in 2005 by North Korea, which signed an accord to relinquish its nuclear arms, only to renege a year later by testing a bomb.
But Monday, Mr. Netanyahu held his fire. He called for the sanctions to be kept in place until Iran showed "verifiable" progress in the nuclear negotiations. And he credited Mr. Obama's pressure tactics, along with the threat of military action, for bringing Iran to the negotiating table.
"Iran is committed to Israel's destruction," Mr. Netanyahu said. "So for Israel, the ultimate test of a future agreement with Iran is whether or not Iran dismantles its military nuclear program."
Mr. Obama, for his part, acknowledged Israel's special security concerns and insisted that he had not been beguiled by Mr. Rouhani, with whom he has exchanged letters and, during a 15-minute phone conversation Friday, exchanged pleasantries in Persian.
After last week's heady developments, the White House is trying to manage expectations about the grinding diplomacy to come.
"We enter into these negotiations very clear-eyed," he said, as Mr. Netanyahu nodded. "They will not be easy, and anything we do will require the highest standards of verification in order for us to provide the sort of sanctions relief that I think they are looking for."
While Mr. Obama was reassuring Mr. Netanyahu in private, Vice President Joe Biden delivered a rousing declaration of U.S. support for Israel to J Street, a moderate pro-Israel lobbying group that favors a two-state solution to the conflict. Drawing applause when he mentioned Mr. Obama's call to Mr. Rouhani, Mr. Biden said, "We don't know whether Iran is willing to do what is necessary to get there, but we, along with the permanent members of the U.N. Security Council and Germany," want to find out.
Mr. Netanyahu's show of unity went beyond Iran. He thanked the president for Secretary of State John Kerry's efforts to broker a peace agreement between the Israelis and Palestinians, another issue that has divided them. He and Mr. Kerry met later at the State Department.
Analysts said the White House harmony reflected both that the relationship between the two leaders has genuinely improved in the past year, and that the United States is unlikely to agree to a nuclear deal with Iran over Israel's objections, if only because Israel will reserve the right to strike militarily if it believes that Iran poses a dire threat.
"Whatever negative vibes Mr. Netanyahu got, he'll spare the president and unload on the world and Iran in his speech tomorrow," said Aaron David Miller, a former Middle East negotiator now at the Woodrow Wilson International Center for Scholars.