WASHINGTON, May 6 — As the Central Intelligence Agency undergoes its latest round of turmoil, legislators and former intelligence officials say that serious gaps in the United States' knowledge of Iran are among the most critical problems facing a new director of the spy agency.
A year after a presidential commission gave a scathing assessment of intelligence on Iran, they say, American spy agencies remain severely handicapped in their efforts to assess its weapons programs and its leaders' intentions. Whoever takes the helm of the C.I.A. after the resignation on Friday of Porter J. Goss will confront a critical target with few, if any, American spies on the ground, sketchy communications intercepts and ambiguous satellite images, the experts say.
When he took the job 19 months ago, part of Mr. Goss's mandate was to make certain that the wildly mistaken prewar assessments about Iraq's weapons would not repeated. But as Mr. Goss leaves the agency, the intelligence watchers say that huge uncertainty remains in estimates of Iran's weapons, complicating the task of persuading the United Nations Security Council to impose sanctions or take other measures.
"How many years are they away from having a nuclear weapon?" asked Senator Pat Roberts, Republican of Kansas, chairman of the Senate intelligence committee, in an interview this week. "We don't know, and the people providing the answers don't know."
Administration officials say Mr. Goss's successor, expected to be named Monday by President Bush, will probably be Gen. Michael V. Hayden of the Air Force, the principal deputy director of national intelligence. A senior intelligence official said on Saturday that General Hayden recently gave the President's Foreign Intelligence Advisory Board a highly critical account of Mr. Goss's performance at the C.I.A. that may have been one catalyst for the director's ouster.
If General Hayden is the president's choice and is confirmed — a process likely to involve a public review of his prior role in domestic electronic surveillance as director of the National Security Agency — he will inherit an agency in considerable disarray. He would bring political clout that might be welcomed by the agency's battered managers, but some officers might resent him as an outsider, a military man and a representative of the director of national intelligence, John D Negroponte, former agency officials said.
General Hayden would face the aftermath of a long list of seemingly unrelated problems that marked Mr. Goss's brief tenure.
Mr. Goss's team of brash former Congressional staff members stirred resentment and an exodus of experienced officers, and months after Mr. Goss's arrival he found himself cast as second fiddle to Mr. Negroponte. The Valerie Wilson leak investigation strained relations with the White House.
The agency's role in the secret detention and interrogation of terrorism suspects led to accusations of misconduct. Leaks prompted Mr. Goss to conduct a campaign of polygraph examinations that led to the dismissal of a senior official.
The doubts about intelligence on Iran persist despite some successes, including revealing data from a laptop computer provided by an Iranian exile that American officials say casts new light on Iran's nuclear program. American officials shared the data last year with the International Atomic Energy Agency, whose inspectors remain the major source of the United States' knowledge of the Iranian program.
Also, in January, Mr. Negroponte sought to focus multiple agencies' efforts by appointing a veteran C.I.A. analyst, S. Leslie Ireland, as the first "mission manager" for Iran. With input from General Hayden, Ms. Ireland has created an Iran strategy board, with 20 analysts from various agencies who meet monthly and talk daily about how to get better information.
But if the administration and the atomic energy agency have emphasized what they have learned about Iran's quest for nuclear weapons, skeptical members of Congress stress the larger universe of the unknown. They are not convinced much has changed since last year's presidential commission on weapons intelligence, led by Laurence H. Silberman, a federal judge, and Charles S. Robb, the former Virginia senator and governor, found a lack of solid evidence on Iranian programs.
Representative Jane Harman, the top Democrat on the House Intelligence Committee, said a classified briefing in early March on Iran's missiles and their ability to carry warheads "raised as many questions as it answered." She and other representatives sent a classified letter posing additional questions on March 9 to Mr. Negroponte, but they have received no reply, she said.
"I continue to believe that our sources are stale and our case is thin" on the weapons programs and internal politics of Iran, Ms. Harman of California, said.
Some experts say they have confidence in official American estimates that Iran is unlikely to have a nuclear weapon until the next decade. "I think the 5 to 10 year estimate is very solid," said Gary S. Samore, vice president of the MacArthur Foundation and a former government expert on nuclear proliferation.
But an array of former intelligence officials said the holes in American knowledge are numerous.
"Whenever the C.I.A. says 5 to 10 years, that means they don't know," said Reuel Marc Gerecht, a former Iran specialist in the clandestine service of the C.I.A. He said French and Israeli experts believe an Iranian bomb may be as little as one to three years off.
Flynt L. Leverett, a former C.I.A. analyst now at the Saban Center for Middle East Policy at the Brookings Institution, said American military planners clearly lack the detailed data needed to be able to cripple the Iranian nuclear program with air strikes should such a step be ordered.
"It's likely there are facilities we don't know about," Mr. Leverett said. "And if we knocked out the facilities we do know about, we wouldn't really know how much we'd set back their nuclear program."
Jon Wolfsthal, of the Center for Strategic and International Studies, said American uncertainty extends to the relationship of President Mahmoud Ahmadinejad, the firebrand president since August, and Ayatollah Ali Khamenei, the supreme leader, and their respective goals.
"We not only don't know who makes the decisions," said Mr. Wolfsthal, who traveled to Iran last month. "We don't even know who's in the room when decisions are made."
A senior American intelligence official, authorized to speak only on condition of anonymity, did not quarrel with that bleak assessment but said the government's Iran specialists were working to improve the situation.
"It is a hard target, but we are not complacent," the official said. "On a daily basis we're trying to recruit new sources."
Such intelligence shortcomings date at least to the period before the Islamist revolution that overthrew the shah in 1979. With no American embassy in Tehran, C.I.A. officers cannot operate under diplomatic cover inside Iran. And because American sanctions ban most business and academic ties, infiltrating spies under what is known as nonofficial cover is difficult.
"I can't think of many people who'd go in under nonofficial cover and pitch senior officers of the I.R.G.C.," the Iranian Revolutionary Guard Corps, said a former veteran C.I.A. operations officer with experience in Iran. Without diplomatic immunity, an unmasked spy could be imprisoned or worse, said the former officer, who was granted anonymity to discuss intelligence methods.
Operating in the 1980's from a C.I.A. base in Frankfurt, called Tefran, for Tehran-Frankfurt, C.I.A. officers managed to build a network of agents inside Iran. But Iranian counterintelligence broke up the ring in 1989, former intelligence officers say. In the early 1990's the Frankfurt base was disbanded, and since then, operations have been directed from C.I.A. headquarters in Langley, Va., focusing on areas where there are large numbers of Iranian immigrants, including Los Angeles, the officers said.
But by all accounts, the results have been modest. Mr. Leverett said, "it seems likely that the United States does not have a significant human intelligence capability inside Iran."
The National Security Agency's efforts to intercept Iranian government communications were hampered in the last two years because Iran learned that the United States had broken its codes and changed them. Satellite photography has provided detailed images of suspected nuclear facilities, but such photographs leave many unanswered questions. Unmanned aerial vehicles are flown into Iran to sniff for gases that would provide clues to nuclear processing, former intelligence officials said.
But such technology cannot remedy Americans' ignorance of Persian language and Iranian culture, said Ahmad Karimi-Hakkak, director of the Center for Persian Studies at the University of Maryland, where some intelligence officers will begin immersion language classes this summer. Just 300 to 400 university students nationwide are studying Persian, he estimated, and most of those will drop out before becoming fluent.
"The problem of the failure to understand Persian culture has been with us since before the revolution in 1979," Mr. Karimi-Hakkak said. "But its consequences have never been more serious than today."