* Deterrence seen 'still viable,' not just Cold War ploy
* Nuclear option should seem unattractive to Iran leaders
WASHINGTON, March 4 (Reuters) - The United States should emphasize a military 'deterrence' policy, including a possible guarantee of nuclear protection for friendly Middle Eastern countries, in persuading Iran to abandon suspected nuclear weapons aims, a think tank recommended on Wednesday.
The Washington Institute for Near East Policy recommended the deterrence tactic -- emblematic of the U.S.-Soviet nuclear standoff -- in a task-force report whose members included two diplomats who are now senior Obama administration officials.
"Talk of deterrence should be used to make Iran's nuclear program less attractive to its leaders," said the report. "One issue needing much more thought is how a U.S. nuclear guarantee, or 'umbrella,' would work and whether it is appropriate in the Middle East."
The report was prepared by a group of 15 U.S. lawmakers, diplomats and military and foreign policy experts.
It said Iran's nuclear program already threatens stability by raising doubts over U.S. commitment and power.
Dennis Ross, the State Department's special adviser on Iran and the Middle East and Robert Einhorn, the department's top nonproliferation official, signed off on early drafts but withdrew from the task force when asked to join President Barack Obama's administration, the report said.
The United States and some allies suspect Iran of seeking a nuclear weapon, but Iran says it is seeking peaceful nuclear power only. Israel has called an Iranian bomb unacceptable.
Little-noticed U.S. statements over the last year have signaled an intention to protect "friends" and not just formal allies with nuclear weapons if needed, especially to the Middle East, said task force member Eugene Habiger, former head of the U.S. military's Strategic Command in charge of nuclear arms.
"The nuclear umbrella of deterrence has been extended. I think it's going to play a major role where were going in the future with the Iranian nuclear program," he told a forum on the report. The idea of deterrence, or threatening unacceptable damage to avert war, took hold during the Cold War when it referred mainly to a massive nuclear strike.
However, Habiger said, "Deterrence is not a Cold War concept ... it's still a viable doctrine."
Secretary of State Hillary Clinton said, when running against Obama for the Democratic presidential nomination last year, that Washington should bring other Middle Eastern nations besides Israel under a security "umbrella" to deter Iran.
Israel is widely believed to have its own nuclear weapons. The report said many states in the region think there is already an implied U.S. nuclear guarantee, "but it is by no means clear Tehran shares this perception."
The report also recommended more regional diplomacy and U.S participation in international incentives for Iran, including security assurances, to give up its nuclear program.
But it said time was running out, with Iran producing low-enriched uranium, which could be converted into weapons-grade highly enriched uranium.
A trigger for an Israeli strike on Iran could be Russian delivery of air-defense systems, it said. It recommended giving Israel more modern planes to overcome the defenses.
It also said enhanced missile defenses for Israel and Gulf states may raise Iranian doubts about the effectiveness of any nuclear weapons program. (Editing by Eric Walsh)
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