Did Dennis Ross, just retired as President Obama’s top adviser on the Middle East, quit over differences with the Obama administration on Iran? When I asked him that question after he spoke last week at the Washington Institute for Near East Policy (WINEP), he said no, and he told another questioner that he’d left because of a promise to his family. But in his WINEP talk, Ross was talking tough on Iran, implying that President Obama was seriously considering the possibility of military action to stop Iran from making a nuclear weapon.

Leave aside, for a moment, the fact that there’s no concrete intelligence showing that Iran has an active weapons program. Maybe it does—it’s hard to explain its insistence on maintaining the nuclear research program, in the face of sanctions and international condemnation otherwise. But in any case, Iran is likely several years at least from being able to manufacture a weapon, if indeed it has the know-how. And so far, there’s no sign at all that Iran is diverting even an ounce of its low-enriched uranium into the production of bomb-grade, highly enriched uranium.

In an address two weeks ago to the Brookings Institution, however, Secretary of Defense Panetta laid out four reasons why an attack on Iran is a bad idea.

“Part of the problem here is the concern that at best, I think—talking to my friends—the indication is that at best it might postpone it maybe one, possibly two years,” he said.

Of greater concern to me are the unintended consequences, which would be that ultimately it would have a backlash and the regime that is weak now, a regime that is isolated would suddenly be able to reestablish itself, suddenly be able to get support in the region, and suddenly instead of being isolated would get the greater support in a region that right now views it as a pariah.

Thirdly, the United States would obviously be blamed and we could possibly be the target of retaliation from Iran, striking our ships, striking our military bases. Fourthly—there are economic consequences to that attack—severe economic consequences that could impact a very fragile economy in Europe and a fragile economy here in the United States.

And lastly I think that the consequence could be that we would have an escalation that would take place that would not only involve many lives, but I think could consume the Middle East in a confrontation and a conflict that we would regret.

So we have to be careful about the unintended consequences of that kind of an attack.

Nowhere in Ross’s presentation to WINEP did the former White House adviser mention any negative consequences of a strike on Iran. Even though Panetta and Admiral Mike Mullen, former chairman of the Joint Chiefs of Staff, have repeatedly stressed that war against Iran could have unpredictable and dangerous results, Ross said that Obama is serious about using force to prevent Iran from acquiring a military nuclear capability.

“[Obama] has not been reluctant to use force when he says that all options remain on the table,” said Ross. “It means that it’s an option he is prepared to exercise.” Later, in a private discussion, Ross told The Nation that even though Panetta, Mullen and others in the administration seem to oppose a strike against Iran, “the president doesn’t take his own words lightly. Has he made a decision yet? No.”

Ross, before going into the administration in 2009, spent many years at the Washington Institute, a hawkish, pro-Israel think tank, and he has returned there as its counselor and resident expert on the region. While at the White House, he had a reputation as a hardliner on Iran policy, and there has been speculation in Washington that he left the White House because of differences with other US officials, including Pentagon leaders who have expressed reluctance to attack Iran even if that appears to be the only way to halt Iran’s nuclear research program. But in his WINEP appearance on Tuesday, Ross disputed that, saying instead that he quit after three years in order to keep a promise he’d made to his family.

Though Iran has denied that it seeks to militarize its nuclear program and though there is no concrete evidence that Iranian leaders have decided to seek nuclear weapons, Ross said in his view there is no ambiguity. “The Iranians, by their behavior, have made it pretty clear that they want to have a nuclear weapons program,” he said. He emphasized that the goal of US policy is to prevent Iran from building a bomb, not containing it once it has developed a military nuclear capability. “It’s not about containment, it’s about prevention,” he said.

Because neither sanctions nor diplomacy have dissuaded Iran from its nuclear program, many analysts in Washington have begun to talk about containing a nuclear Iran, much as the United States pursued a containment, balance-of-power policy toward the Soviet Union in the cold war. And it’s been reported that officials at the White House, the State Department and the Defense Department are quietly discussing precisely that idea if Iran eventually decides to go nuclear.

But Ross laid out a apocalyptic scenario for nuclear Armageddon in the Middle East if Iran gets the bomb. Were Iran to acquire even a limited nuclear capability, it would dramatically destabilize the Middle East, he said, and that’s why a containment policy is the wrong approach. “The fact is that Israel looks at Iran as an existential threat, and it is,” he said. If both Israel and Iran have nuclear bombs, it would put the region on a hair trigger, and he asked, “Can Israel wait?” if a nuclear-armed Iran seemed to raise its level of readiness for war. “The possibility of nuclear war in the Middle East goes up dramatically.”

Ross stressed that there is still room for the administration’s combination of sanctions and negotiation to work. “We still have time and space available to us to ratchet up the pressure,” he told WINEP. But some analysts have argued that sanctions, pressure tactics and what appears to be a campaign of covert action against Iran could provoke Iran into aggressive, rash behaviors that could by themselves lead to conflict. In the field of covert action, recent events include the assassination of several Iranian scientists, a computer worm that damaged Iran’s centrifuge facility, an explosion that killed the top Iranian commander in charge of its missile program, and the recent crash of a US surveillance drone in eastern Iran. Ross refused to comment on whether or not the United States has a covert action program under way, but when asked about it he replied cryptically, “The full range of options need to be pursued. All options need to be explored.”

One argument against war with Iran and against harsh economic sanctions that would include curtailing or cutting off Iran’s oil exports is that the loss of Iran’s oil on the world market would send prices skyrocketing. But Ross suggested that quiet talks with Saudi Arabia, the United Arab Emirates and Kuwait—all of which have expressed alarm about Iranian ambitions in the gulf—might lead Arab oil producers to ratchet up their output to offset Iranian exports. And, he said, Libya’s oil output is already coming back onto the market, further easing pressure on prices. Thus, he said, it’s might be possible to “phase in an Iran oil shutoff without a spike in prices.”

Alongside Ross’s comments about the idea of getting other, especially Arab, oil producers to offset Iran’s oil exports in case sanctions (or a blockade) shuts down Iranian production,, the Wall Street Journal reports today:

The Obama administration, its European allies and key Arab states are intensifying discussions on how to maintain stability in the global energy markets in a possible precursor to a formal embargo on Iran’s oil exports and its central bank. Such an embargo would constitute the most direct economic confrontation yet between Iran and the West and would amplify tensions as Iran repeatedly threatens to close the Strait of Hormuz, through which passes about one-fifth of the world’s oil supply.

Ross suggested that already existing sanctions are having a strong effect, and that Iran is feeling the pain. In an interview with The Nation, he said that Iran’s discomfort over the sanctions regime might have helped to provoke the recent mob attack on the British embassy in Tehran, which, Ross said, was orchestrated by the government. “What it reflects,” he said, “is that they’re under a lot of stress.” But other analysts argue that the combination of economic sanctions and an apparent covert action program might provoke Iran, and that the attack on the embassy might be one sign that Iran is prepared to answer what it perceives as violence directed against it by the United States with violence of its own.

Steven Walt, a professor of international relations at Harvard University, wrote recently that there could be other signs, too, that Iran is striking back. “A case in point is the alleged Iranian plot to get Mexican drug lords to assassinate the Saudi ambassador in Washington,” he wrote in Foreign Policy. “Americans immediately concluded that this scheme was a sign of dastardly Iranian perfidy, when it might just as easily have been a harebrained Iranian riposte to what we were already doing.”

During the election campaign in 2008, Obama promised repeatedly that he would seek talks with Iranian leaders over differences with the United States, and since taking office he said launched several rounds of diplomacy aimed at coaxing Iran into a deal over its uranium enrichment program. So far, it hasn’t paid off. The reality, however, is that despite the doomsday accounts of Iran’s program, as yet Iran hasn’t diverted any of its low-enriched uranium into anything resembling a military program and it doesn’t have any bomb-grade, highly enriched uranium. Nor, experts believe, does it have the means to deliver a bomb even if it had one. And it still isn’t clear if Iran has the know-how to manufacture a weapon even if it did stockpile enough highly enriched uranium. For all those reasons, most experts—including those at Israel’s Mossad and the US intelligence community—believe that Iran is still several years away, at least, from a military nuclear capability, if that is what it intends to do. According to that logic, even those who agree with Ross’s view a unilateral US military strike on Iran might be necessary to block Iran’s progress probably can keep their powder dry for a few more years.

But two of Ross’s colleagues at WINEP have recently issued stark reminders that many hawks, neoconservatives and Republicans—including several candidates for the GOP nomination for president in 2012—have criticized the Obama administration for not more vigorously backing up its diplomacy with the threat of war. “For nuclear diplomacy to succeed, Tehran must believe that if it tries to build a bomb, the United States will undertake military action to disrupt such an effort,” wrote Michael Eisenstadt, director of the Military and Security Studies Program at WINEP, wrote in November. “For the threat of force to work, however, it has to be credible, and it has to dramatically alter Iran’s risk calculus. Right now, neither condition is present. The United States ignores this state of affairs at its own, and its allies’ peril.”

And David Makovsky, a WINEP fellow and the director of its Project on the Middle East Peace Process, warned last month that Israel may have only months, not years, to decide on whether or not to attack Iran. In “Israel’s Closing Window to Strike Iran,” Makovsky wrote that Israel’s defense minister, Ehud Barak, “hinted that Israel and the world may reach the limit of their capacity to effectively strike Iran’s nuclear facilities within as little as six months.” Because Iran is dispersing its program and installing it in hardened, more defensible sites, Israel may have to strike very soon or resign itself to the fact that Iran can’t be stopped.