The International Atomic Energy Agency has wrapped up its visit to Iran, with its chief inspector, Herman Nackaerts, saying “we had a good trip” and announcing plans for another “in the very near future.”

The Iranians are in agreement. “We’ve always tried to put transparency as a principle in our cooperation with the IAEA,” said Ali Akbar Salehi, the country’s MIT-educated foreign minister.

We’ve heard this Persian fairy tale before. Faced with increasing international pressure, Iran makes nice with the agency, trying to beguile its inspectors and 35-member governing board with explanations and evasions. Judging by Iran’s continuing failure to live up to its legal obligations under the Nonproliferation Treaty, the goal is to play for time until an Iranian nuclear weapon is a fait accompli and the world lives uneasily ever after.

Details of the IAEA’s mission will probably not be revealed until its next quarterly report in a few weeks. In the meantime, the agency has announced that another meeting will take place in Tehran on Feb. 21-22. Iran’s receptiveness to the team’s visit suggests a willingness to take seriously the allegations about its nuclear program’s “possible military dimensions” -- to use the IAEA’s almost-smoking-gun phrase from its report in November -- rather than dismissing them out of hand as lies and fabrications as it has in the past.

Sanctions That Bite

That gives us another hopeful sign: that the sanctions imposed by the U.S. and its allies, including a European embargo on Iranian oil to take effect this summer, are having an effect. The isolation of Iranian banks from the international financial system has sent prices of basic goods higher and cut the value of the rial against the dollar by more than 50 percent, bringing home to ordinary Iranians the consequences of their leadership’s actions. Supreme leader Ayatollah Ali Khamenei must weigh whether Iran’s economy, and his regime’s rule, can withstand such growing pressure over the one to two years that analysts estimate Iran still needs to build a nuclear weapon.

If ever there were a place and time to, as Richard Nixon famously said about Chile, “make the economy scream,” it would be Iran now. Given the dismal alternatives of military action or a nuclear-armed Iran, sanctions must be stiff enough to lead Iran’s supreme leader to the right conclusion. We welcome the urgency that Congress has attached to this issue, with three new bills in the works that target Iran’s oil industry and finances.

At the same time, sanctions must strengthen rather than fracture the coalition behind them. To execute the delicate diplomacy involved, President Barack Obama’s administration must have leeway in enforcing such measures. To our minds, some of the legislation that’s been proposed doesn’t provide the necessary maneuvering room. The Senate Banking Committee will mark up draft legislation Thursday that will, among other things, impose a six-month deadline on investigating and sanctioning any company listed on U.S. stock exchanges that has conducted activities sanctionable under U.S. law, or has affiliates that have done so. This is a tight timeframe and a very wide net. Although the committee has taken pains to blunt any charges of extraterritoriality, its far-reaching provisions on foreign subsidiaries may raise hackles in Europe and elsewhere.

There’s little doubt that the Iranians’ new willingness to talk to the IAEA is an attempt to sow division between their most hard-line critics and those countries still hoping Iran will change its ways; dissension over potentially overreaching sanctions could produce much the same effect.

Sharing Intelligence

In addition to laying on tighter, smarter sanctions, there are steps the world can take to help the IAEA. These include providing the agency with more intelligence evidence that it can actually show the Iranians -- many intelligence agencies now share information with the IAEA on the condition that it be kept from Iran. This wouldn’t necessarily persuade the Iranians to admit to illicit activities, but it would put a stop to Iran’s complaints on that score and help to maintain the agency’s present effectiveness and future credibility. (The debacle of Iraq, with its slam dunks and still-missing weapons of mass destruction, has left the IAEA’s professional staff understandably concerned about being led up the garden path.)

The IAEA should also be encouraged to use its authority for so-called special inspections, which can be undertaken quickly when the information provided by a state is inadequate, even without the signing of an additional protocol. And, moving forward, the agency’s board of governors needs to make its voting records public. Let those member countries that have refused to help in stopping the spread of nuclear weapons confront greater public scrutiny -- as they will, ultimately, history’s verdict.

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