The leading Republican candidates were weirdly overt with their promises in last weekend's debate about waging covert war against Iran, and even assassinating its scientists. Perhaps it's a sign that foreigners don't take American politics very seriously, but the inflammatory talk created barely a ripple in this part of the world.

Or maybe the savvy, cynical Middle East believes that the covert war has already begun -- with Israel's Mossad conducting lethal operations of the sort Republicans are clamoring for the CIA to adopt. The danger is that if the other side thinks the conflict has already started, it will feel compelled to retaliate.

The language the GOP candidates used was astonishing, at least for people who assume that covert activities are ones that aren't talked about openly -- much less touted -- in campaign debates.

This field of Republicans says strange things in debates, but it was still startling to hear the leading candidates' statements. Mitt Romney pledged to "work on a covert basis to encourage the dissidents." Herman Cain said he would "assist the opposition movement in Iran that's trying to overthrow the regime." Newt Gingrich promised "maximum covert operations including taking out their scientists, including breaking up their systems. All of it covertly, all of it deniable."

Romney also promised "covert activity" against Syria, while Gingrich argued for a "mostly covert" effort to topple the Syrian regime.

What is it about "covert" that the Republicans don't understand? What would be the American reaction to similar public threats against the United States if they were made by Iranian or Syrian politicians?

Beyond the war talk of recent weeks, it's clear that the confrontation over Iran's nuclear program truly is "the Cuban missile crisis in slow motion," to use Harvard professor Graham Allison's memorable phrase. Either the Iranians agree to turn back their program, or the West accedes to Iran becoming a nuclear weapons state. The alternative is a collision.

The question is starkly similar to what President John F. Kennedy faced in the October 1962 standoff: He sought a way to convey U.S. determination without outright war. The Pentagon generals were screaming that Kennedy had to bomb the Soviet missile sites in Cuba -- in much the same way that Israeli hawks are agitating today for a bombing campaign against Iran. Kennedy wisely realized that it wasn't all or nothing; he could operate along a continuum of power, in which bombing would be the last step, not the first.

The option Kennedy chose deserves discussion. He decided, against the advice of most advisers, on a "quarantine" of Cuba to prevent the missiles from becoming operational. It was a step well short of war (or even, lethal covert action), and it left the Soviets room to maneuver. It also avoided the political fallout across Latin America that would come from bombing Cuba (similar to the destabilizing effect that bombing Iran would cause for America and Israel).

A quarantine of Iran's nuclear program could take many forms, along a ladder of escalating seriousness. It would seek to enforce U.N. resolutions, peacefully. If crafted wisely, it would have the support of most U.S. allies.

As America chooses its tools along the continuum of power, it will undoubtedly continue its covert activities against Iran. But they lose their impact and rationale if they become a topic for facile domestic political debate.