May 29— The Pentagon is advocating a massive covert action program to overthrow Iran's ruling ayatollahs as the only way to stop the country's nuclear weapons ambitions, senior State Department and Pentagon officials told ABCNEWS. The proposal, which would include covert sponsorship of a group currently deemed terrorist by the U.S. government, is not new, and has not won favor with enough top officials to be acted upon. But sources say it is a viable option that is getting a new look as the administration ramps up its rhetoric against Iran, and it is likely to be one of the top items on the agenda as high-level U.S. policymakers meet today to discuss how to deal with the Islamic republic. The Pentagon's proposal includes using all available points of pressure on the Iranian regime, including backing armed Iranian dissidents and employing the services of the Mujahedeen e Khalq, a group currently branded as terrorist by the United States....The objective of the Pentagon proposal to destabilize the Iranian government is based on the belief that the religious hard-liners are opposed by the majority of the Iranian population and any pressure would make them crack — a view that some analysts find dubious. The debate over Iran comes after Defense Secretary Donald Rumsfeld on Tuesday warned Iran against meddling in Iraq, and presidential spokesman Ari Fleischer described the Islamic republic's efforts to root al Qaeda leaders out of country as insufficient. (more)