Correction: The editorial reported that Iran began diverting part of its stockpile of 20 percent enriched uranium to produce fuel rods following a speech to the United Nations by Israeli Prime Minister Benjamin Netanyahu last September. Some uranium was also diverted before the speech. The editorial has been updated.
THE LATEST round of negotiations on Iran’s nuclear program was, by all accounts, a disappointment. Tehran’s negotiators did not spell out a full response to a proposal by the United States and five partners for limiting its enrichment of uranium, and what they did say revealed a wide gulf between the two sides. In essence, the international coalition is offering Iran a partial lifting of sanctions in exchange for a freeze on the production of medium-enriched uranium, while Iran wants a complete lifting of sanctions in exchange for token steps that would leave its nuclear work unfettered.
The meetings left the diplomatic process in limbo; the Obama administration and its allies rightly refused Iranian requests to schedule further meetings. Yet for now, at least, there is no crisis: Neither Israel nor the United States is under pressure to consider immediate military action against Iran, and there is time to wait and see if Iran’s position will soften following a presidential election scheduled for June.
For that, proponents of diplomacy over war with Iran can thank a man they have often ridiculed or reviled: Israeli Prime Minister Benjamin Netanyahu.
Mr. Netanyahu’s government is not a participant in the talks with Iran, of course; Iran won’t parley with a nation it aspires to “wipe off the map.” But the Israeli leader’s explicit setting of a “red line” for the Iranian nuclear program in a speech to the U.N. General Assembly in September appears to have accomplished what neither negotiations nor sanctions have yielded: concrete Iranian action to limit its enrichment.
A host of commentators both in the United States and Israel scoffed at what they called Mr. Netanyahu’s “cartoonish” picture of a bomb and the line he drew across it. The prime minister said Iran could not be allowed to accumulate enough 20 percent enriched uranium to produce a bomb with further processing, adding that at the rate its centrifuges were spinning, Tehran would cross that line by the middle of 2013.
Iran, too, dismissed what its U.N. ambassador called “an unfounded and imaginary graph.” But then a funny thing happened: The regime began diverting more of its stockpile to the manufacture of fuel plates for a research reactor. According to the most recent report of international inspectors, in February, it had converted 40 percent of its 20 percent uranium to fuel assemblies or the oxide form needed to produce them. As a result, Iran has remained distinctly below the Israeli red line, and it probably postponed the earliest moment when it could cross that line by several months.
Mr. Netanyahu’s red line is only a partial and temporary check on the Iranian threat. The ongoing installation of a new generation of faster centrifuges could soon make it obsolete by providing a new means for Iran to quickly produce bomb-grade uranium. But the lesson here is twofold: The credible threat of military action has to be part of any strategy for preventing an Iranian nuclear weapon, and clear red lines can help create the “time and space for diplomacy” that President Obama seeks. Mr. Obama, who last year stiffly resisted pressure from Mr. Netanyahu to spell out U.S. red lines, ought to reconsider.