This Salon piece says the big problem stemming from Iran's nuclear ambitions is the arms race it will trigger in the Mideast. And with the Iraq WMD debacle, no one is going to take the president of the United States' word about a possible threat.

An excerpt: (free with a daypass)

Since Iran defied international regulators and broke the seals on its nuclear research sites earlier this month, world leaders have once again been sounding the alarm over the country's nuclear intentions and capabilities. But while the debate over diplomacy vs. the "military option" is plenty familiar, the Bush administration has put the United States in a bad position to deal with Tehran's hard-line government, says a top expert on nuclear weapons.

Joseph Cirincione, director for nonproliferation at the Carnegie Endowment for International Peace in Washington, says that the failure to find alleged weapons of mass destruction in Iraq has damaged U.S. credibility -- at a time when nuclear terrorism is the gravest threat facing the U.S. and its allies. "The world is now filled with Doubting Thomases," he says. "I doubt very much if even the United Kingdom would take military actions based solely on the word of the president of the United States."

Beyond the Iraq war, Cirincione says, the problem is that the U.S. and other countries with nuclear arsenals, including Israel, have continued to make nuclear weapons the currency of great power and status. This makes them highly desirable -- even necessary -- from the perspective of countries like Iran, Saudi Arabia, Turkey and Egypt.

But if Iran has the potential to set off a nuclear arms race in the volatile Middle East, Cirincione believes that a military option to stop the mullahs really is no option at all: "Even an airstrike against a soft target like the uranium conversion facility at Isfahan would inflame Muslim anger, rally the Iranian public around an otherwise unpopular government and jeopardize further the U.S. position in Iraq," he says. "We are in a much weaker position today to deal with Iran because of the mistakes of the Iraq war."