WASHINGTON -- United States President Barack Obama's refusal in a White House briefing this month to announce a "red line" in regard to Iran's nuclear program represented another in a series of rebuffs of pressure from Defense Secretary Robert Gates for a statement that the US will not accept its existing stocks of low enriched uranium.
The Obama rebuff climaxed a months-long internal debate between Obama and Gates over the "breakout capability" issue that surfaced in the news media last April.
Gates has been arguing that Iran could turn its existing stock of low-enriched uranium (LEU) into a capability to build a nuclear weapon secretly by using covert enrichment sites and undeclared sources of uranium.
That Gates argument implies that the only way to prevent Iran having enough bomb-grade uranium for nuclear weapons is to insist that Iran must give up most of its existing stock of LEU, which could be converted into enough bomb-grade uranium for one bomb.
But Obama has publicly rejected the idea that Iran's existing stock of LEU represents a breakout capability on more than one occasion. He has stated that Iran would have to make an overt move to have a "breakout capability" that would signal its intention to have a nuclear weapon.
Obama's most recent rebuff of the Gates position came in the briefing he gave to a select group of journalists on August 4.
Peter David of The Economist, who attended the briefing, was the only journalist to note that Obama indicated that he was not ready to lay down any public red lines "at this point". Instead, Obama said it was important to set out for the Iranians a clear set of steps that the US would accept as proof that the regime was not pursuing a bomb.
Obama appeared to suggest that there are ways for Iran to demonstrate its intent not to build a nuclear bomb other than ending all enrichment and reducing its stock of low enriched uranium to a desired level.
Iran denies any intention of making nuclear weapons, but has made no secret that it wants to have enough low enriched uranium to convince potential adversaries that it has that option.
At a 2005 dinner in Tehran, Hassan Rowhani, then secretary of Iran's Supreme National Security Council, told George Perkovich of the Carnegie Endowment for International Peace that Iran didn't need a nuclear weapon, as long as it had the "mastery of the fuel cycle" as a deterrent to external aggression.
Gates raised the issue of the Iranian ability to achieve a breakout capability in a three-page memorandum addressed to national security adviser Jim Jones in January 2010, as first reported in the New York Times on April 18.
In reporting the Gates memo, David E Sanger of the New York Times wrote, "Mr Gates's memo appears to reflect concerns in the upper echelons of the Pentagon and the military that the White House did not have a well-prepared series of alternatives in place in case all the diplomatic steps finally failed."
In the statement issued on the memo on April 18, Gates said it "identified next steps in our defense planning process where further interagency discussion and policy decisions would be needed in the months and weeks ahead".
The Sanger article appeared eight days after differences between Obama and Gates over the Iranian breakout capability issue had surfaced publicly in April.
Obama used an April 1 interview with CBS News to distinguish between Iran's "trying to develop the capacity to develop nuclear weapons" from a decision to actually possess nuclear weapons.
"They might decide that, once they have that capacity that they'd hold off right at the edge - in order not to incur more sanctions," he observed. Obama talked about a new round of international sanctions as his response to that problem.
Hardliners in Washington wanted Obama to go further. David E Sanger of the New York Times invited Obama in an April 5 interview to draw the US red line at an Iranian breakout capability, Obama refused to do so.
Sanger asked Obama whether the United States could "live with an Iran that runs right up to the edge" - precisely the scenario Obama had suggested as a distinct possibility four days earlier.
Obama's answer made it clear that he understood that Sanger was pushing the Gates line that there is no obvious firebreak between Iran's low enriched uranium stocks and a breakout capability.
"North Korea was said to be simply a nuclear-capable state until it kicked out the IAEA [International Atomic Energy Agency] and became a self-professed nuclear state," said Obama.
But Gates went public a few days later with a sharply different position on the issue.
When David Gregory of interviewed both US Secretary of State Hillary Clinton and Gates on NBC's Meet the Press on April 9, he had apparently been informed about differences of view within the administration on the issue of an Iranian "nuclear capability".
Gregory asked Clinton, "Is a nuclear-capable Iran as dangerous as a nuclear state of Iran?" to which Clinton answered, "Well, clearly weapons are more dangerous than potential."
Gregory then asked Gates whether a nuclear-capable Iran is "just as dangerous as being a nuclear state to your mind?"
Gates answered, "Only in this respect: how you differentiate how far, how far have they gone? If they - if their policy is to go to the threshold but not assemble a nuclear weapon, how do you tell that they have not assembled?"
Gates said he didn't know "how you would verify that".
That exchange would have confused anyone who was not an insider to the Washington policy debate on Iran. The real issue was not whether the United States could "tell that they have not assembled" but whether Iran could turn its stock of low enriched uranium into weapons-grade uranium without kicking out international inspectors first and signaling their intentions.
Israel and extreme alarmists in the United States have long argued that Iran could use covert enrichment sites to enrich uranium to bomb-grade levels and might have access to undeclared uranium stocks. But a source familiar with the issue told Inter Press Service that the Defense Department had not been claiming that there is any intelligence indicating secret Iranian sites or uranium supplies.
Gates appears to have been trying to maneuver Obama into adopting a policy under which the United States would have a reason for threatening Iran unless it agreed to divest itself of its low enriched uranium stocks and end enrichment.
Although he has opposed an attack on Iran in both the George W Bush and Obama administrations, Gates has also been the primary advocate of creating "leverage" over Iran as well as over Russia and China in regard to tougher sanctions.
In an interview with Sanger in early 2008, quoted in Sanger's book, The Inheritance, Gates said the main problem he had with the 2007 national intelligence estimate on Iran was that it "made our effort to strengthen sanctions more difficult, because people figured, well the military option is now off the table".
Thus far the Obama administration has not given emphasis to the threat of US attack on Iran. Instead it has sought to use the threat of an Israeli attack on Iran as leverage, even as it warns the Israelis privately not to attempt such an attack.
Gareth Porter is an investigative historian and journalist specializing in US national security policy. The paperback edition of his latest book, Perils of Dominance: Imbalance of Power and the Road to War in Vietnam, was published in 2006.