LAUSANNE, Switzerland -- "Iran is half the size of Europe."
You hear this line repeatedly from Israeli officials. Oftentimes, its their way of describing the difficulties of intelligence gathering on Iran's expansive nuclear program, spread across a vast land.
Israelis first note that they cannot divulge information concerning intelligence operations. Then they emphasize just how hard it is to say with confidence that, in fact, they know the breadth and sophistication of Iran's nuclear work.
We know that several plants have been found over the course of a decade, covertly built and nearly operable. Presumably, several others have not been found, either by the Israelis or by the Americans.
On Wednesday in Washington, US Secretary of State John Kerry told the Global Chiefs of Mission Conference that the priority of the Obama administration is to reach a comprehensive nuclear deal with Iran that "shuts off the four pathways to a nuclear weapon: the pathway at Fordow, the pathway at Natanz, the pathway at Arak."
"And finally," he continued, "the covert pathway, which is the hardest of all but which I can assure you we are deeply focused on."
That fourth pathway is perhaps the most important— and the least reported— aspect of talks with Iran currently under way here in Switzerland.
Journalists often cite the number of centrifuges Iran will be allowed to retain, the frequency with which they will be inspected by international monitors, the grade to which they will be able to enrich uranium and the technological sophistication, or efficiency, of the machines.
But that public debate is moot should Iran retain the ability to develop nuclear weapons secretly. Of far greater concern to US President Barack Obama is what he does not know— and what Prime Minister Benjamin Netanyahu does not know, either.
"Right now, Iran could be hiding nuclear facilities that we don’t know about, the US and Israel," Netanyahu said in his speech to a joint meeting of Congress on March 3. "As the former head of inspections for the IAEA said in 2013, he said, 'If there’s no undeclared installation today in Iran, it will be the first time in 20 years that it doesn’t have one.'"
On this issue in particular, the Obama administration seems to agree with Netanyahu— and they have shared the same risk assessment for quite some time.
"The most likely scenario is they would do that [break out to a nuclear weapon] covertly," James Clapper, US director of national intelligence, said in May 2013. Covert breakout, he said, would "actually lengthen the time in which they could develop a testable single weapon."
"Clearly, if they were to do a breakout using the facilities they have now to enrich uranium— which is, as you indicated, under safeguard and under IAEA supervision— that clearly is a real bellwether," Clapper said at the time. "That would be a big warning."
Thus, Western powers argue that a deal is better than not for one reason above all: Visibility.
The US seeks access for the UN's International Atomic Energy Agency to the entire chain of custody on Iran's enrichment program. US officials say this access is the world's best chance to detect the siphoning of raw material to covert facilities— of far greater concern to Washington than Iran's facilities publicly declared.
Asked by The Jerusalem Post last week whether the US government is confident that it has identified all of Iran's uranium mines, one US official said it is not.
Two mines known to the US are at Gachin and Saghand, where a nearby mill, at Ardakan, is near completion and is scheduled to begin production shortly. The point of a deal, the official said, is to keep track of the product of those mines and mills.
An entire chain of custody would have to be covert, from the extraction of ore to its conversion to yellowcake, to its conversion to fuel and ultimately its weaponization, for Iran to circumvent this deal and build a weapon, the official continued. Even then, the US seeks access for the IAEA to additional facilities suspected of aiding in covert processes.
Patrick Clawson, director of research at the Washington Institute for Near East Policy and an expert on Iran, says the consensus view in Washington is that Iran "would prefer to encroach than to openly transgress" toward the bomb.
"Many Iranian covert facilities and activities have been exposed," Clawson says. "One can read that fact as showing that they often do covert things; one can also read it as maybe they are not so good at keeping these activities covert. So building an entirely clandestine program would be risky."
Israel says that Iran could choose to selectively cooperate with UN inspectors; It could kick them out abruptly during the deal, needing less than a year to acquire the bomb; Or it could follow the deal to a tee, and be free of inspections in roughly a decade.
Other critics of the president's Iran policy– including some advocates of Israel in Washington– argue that "noise" will interfere with intelligence operations once sanctions are lifted.
More transactions will be under way between Iran and other nations. Tehran will have the wealth and flexibility to buy components for a covert program overseas, they argue.
One thing is clear: The inspections regime under negotiation here in Switzerland will be the most invasive, ambitious operation ever undertaken by the IAEA. Should a deal come to pass, no other past effort from the agency even comes close.