The eagerness for talks demonstrates a profound change in Iran's political orthodoxy, emphatically erasing a taboo against contact with Washington that has both defined and confined Tehran's public foreign policy for more than a quarter-century, they said.

Although the Tehran government has routinely jailed its citizens on charges of contact with the country it calls the "Great Satan," Ahmadinejad's May 8 letter was implicitly endorsed by Iran's supreme leader, Ayatollah Ali Khamenei, and lavished with praise by perhaps the most conservative ayatollah in the theocratic government.

"You know, two months ago nobody would believe that Mr. Khamenei and Mr. Ahmadinejad together would be trying to get George W. Bush to begin negotiations," said Saeed Laylaz, a former government official and prominent analyst in Tehran. "This is a sign of changing strategy. They realize the situation is dangerous and they should not waste time, that they should reach out."

Laylaz credited, at least in part, Iran's nuclear program, which recently crossed a key threshold by enriching uranium.

"Now we have something to negotiate," he said. "The nuclear program of the regime has been successful, because five years ago nobody wanted to hear our voice."

Several diplomats said senior Iranian officials have asked a multitude of intermediaries to pass word to Washington making clear their appetite for direct talks. Laylaz said Ali Larijani, chairman of Iran's Supreme National Security Council, passed that message to the head of the U.N.'s International Atomic Energy Agency, Mohamed ElBaradei, who arrived in Washington on Tuesday for talks with Secretary of State Condoleezza Rice and national security adviser Stephen Hadley.

Iranian officials made similar requests through Indonesia, Kuwait and U.N. Secretary-General Kofi Annan, Laylaz said.

American intelligence analysts also say Larijani's urgent requests for meetings with senior officials in France and Germany appear to be part of a bid for dialogue with Washington.

"They've been desperate to do it," said a European diplomat in Tehran.

The administration repeatedly has rejected talks, saying Iran must continue to negotiate with the three European powers that have led nuclear diplomacy since the Iranian nuclear program emerged from the shadows in 2002.

"The United States and the international community have made our common position clear: We're determined that the Iranian regime must not gain nuclear weapons," Bush said Tuesday at a White House meeting with Israeli Prime Minister Ehud Olmert.

But U.S. officials who spoke on condition of anonymity said government experts have exerted mounting pressure on the Bush administration to reply to the letter. "The content was wacky and, from an American point of view, offensive. But why should we cede the high moral ground, and why shouldn't we at least respond to the Iranian people?" said an official who has been pushing for a public response.

Analysts, including U.S. specialists on Iran, emphasized that the contents of the letter are less significant than its return address.

"Much stranger first steps have led to dialogues than this letter. And as weird as the letter may be, if the Iranians want to begin discussions based on the theme of righteousness, that's something we should not be afraid to engage on," said Paul Pillar, who was the senior Middle East intelligence analyst with the CIA until last fall. "We have pretty strong arguments about justice and righteousness of our own, so we should not shy away from that."

Inside Iran, the letter effectively widened an opening toward the United States that began in March with Larijani's unusually public acceptance of an American invitation to direct talks on the situation in neighboring Iraq. That acceptance provoked sharp criticism from hard-liners until it was publicly endorsed by Khamenei.

By contrast, Ahmadinejad's letter sparked lavish praise from perhaps the most conservative cleric in Iran's government, Ayatollah Ahmad Jannati, who chairs the Guardian Council, which oversees Iran's electoral process.

"The taboo is gone, for the first time when someone like Jannati endorses the message," said an Iranian political analyst who said he could not be quoted by name because his employer had not authorized him to speak publicly.

This article appeared on page A - 12 of the San Francisco Chronicle