"At current oil prices, an attack would be unlikely to stop the Iranian program," the report, titled "Iran's Political, Demographic, and Economic Vulnerabilities," said. "The government would be able to finance the reconstruction of the facility and continue the current program without major budgetary consequences."

The report warned of a spike in crude oil prices and a decline in investor confidence in Gulf Cooperation Council states. Rand said Iran could block Iraqi oil exports and GCC shipments in the Gulf.

"An Israeli action would also have a detrimental effect on popular Iranian opinion of the United States because Iranians would see the attack as having had the blessing of the United States, although the turnabout in public opinion might be less precipitous than in the event of a U.S. attack," the report said. "Bombing Iran's nuclear facilities would have financial repercussions both for Iran and for the rest of the world."

"The political ramifications within Iran of an attack are less clear," the report said. "[Iranian President Mahmoud] Ahmadinejad has come under fire from other politicians for baiting the United States. An attack might be perceived as his comeuppance. In our view, a more likely response would be a strong push to retaliate against the United States [or Israel]. Critics of such a policy would likely choose to keep silent."

The U.S. intelligence community appeared to dispute some of the assumptions of the Rand report. CIA director Michael Hayden said Teheran might not be successful in using even its Lebanese-sponsored militia, Hizbullah, to retaliate against any U.S. strike on Iranian nuclear facilities.

"Is it in Hizbullah's interest to become involved in a global war against the United States of America?" Hayden asked in an interview with the Bloomberg financial news service. "That's a question to be answered."

For its part, Rand proposed a reconciliation with Teheran and warned the United States not to inflame ethnic tensions in Iran. Authors Keith Crane, Rollie Lal, Jeffrey Martini also called on Washington to halt threats to overthrow the Islamic regime or impose additional sanctions.

"At least in the near term, the Iranian regime is likely to be relatively stable and resistant to external pressures for dramatic change," the report said. "But societal conditions for a more-constructive relationship with the United States exist: In contrast with the Arab Middle East, the United States is popular in Iran. Long-term trends suggest that Iran is likely to become more democratic and less obdurate."