Time after time, the 35-nation International Atomic Energy Agency has demanded that Iran stop enriching uranium. Yet Tehran keeps on thumbing its nose at the U.N. body, saying its uranium enrichment is just a peaceful effort to produce electricity.

To many nations, especially Israel, it seems only a matter of time before Iran breaks out as a nuclear power, ratcheting up tension across the Middle East. An Israel-Iran showdown over Tehran's outlaw nuclear-weapons program now seems increasingly imminent.

Last week, for example, Israel charged that Iran was merely "buying time" and will never abandon plans to develop nuclear weapons. It called for the U.N. Security Council "to put an end to this nightmare."

Addressing reporters at the U.N., Israeli Foreign Minister Silvan Shalom kept all options on the table by avoiding answering whether Israel would take military action against Iran if it continued to pursue nuclear weapons.

Also last week, the administration informed Congress that it was selling Israel 5,000 precision-guided "smart bombs," including 500 satellite-guided, one-ton JDAM "bunker busters" of Baghdad fame. (JDAMs are capable of penetrating six feet of concrete.)

In response to the arms sale, Iran warned Israel against attacking its nuclear facilities, saying it would react "most severely" to any Israeli military action against Iran.

Then, over the weekend, Iran pointedly announced that its Shahab-3 ballistic missile was now operational. The missile can reach Israel, and Iran has 25 to 100 of them. Defense Minister Ali Shamkhrani crowed that Iran was now "ready to confront all regional [read: Israeli] and extra-regional [read: American] threats."

OK, so you say, a little chest-beating isn't the same as the beating of war drums. True. But bear in mind, Israel takes the threat of nuclear weapons in its neighborhood quite seriously. Just ask Saddam Hussein.

In 1981, Israeli fighters conducted a low-level, 700-mile, daylight raid through Saudi Arabian and Jordanian air space into Iraq. In a minute and a half, the fighters laid waste to the French-supplied Osiraq nuclear reactor - the centerpiece of Iraq's burgeoning nuclear-weapons program.

So what would happen if Israel decided to conduct a pre-emptive surgical strike on Iran's nuclear facilities?

Some say that an Israeli attack on a Muslim country would set the Middle East ablaze in an anti-Jewish frenzy. Possible, but not likely.

Sure, all Muslim governments would vociferously condemn the Israeli strike. But most would breathe a quiet sigh of relief. No one in the Middle East (except maybe Syria) wants to see fundamentalist, hegemonic Iran go nuclear. This is especially true for Iran's cross-Gulf rival, Saudi Arabia.

No Arab country would strike back at Israel, but Iran's Lebanese terrorist proxy, Hezbollah, would almost certainly target Israeli (and perhaps U.S.) interests in the region.

Iran itself could decide to retaliate on Israeli cities with missile strikes. And while Israel has a limited missile defense system, missiles raining in on Tel Aviv, a city of 3 million, could be devastating. But Israel could threaten to respond to Iranian strikes on Israeli civilian targets with nuclear weapons.

The other problem is exactly how to inflict sufficient damage on the Iranian nuclear program. Iran has as at least 24 suspected nuclear facilities scattered around the country. Some are underground; others are (intentionally) located by major population areas to ensure civilian casualties during a raid.

But the cost of doing nothing may be the most expensive. An Iranian nuclear breakout would mean a radical shift in the balance of power in the Middle East. Saudi Arabia would certainly move to go nuclear (with likely help from Pakistan).

Tehran might, as well, put Damascus under its new nuclear umbrella or, worse yet, give Syria the bomb. (Happily, even Iran's likely to see giving a nuke to Hezbollah as way too risky.)

Clearly, there are no easy choices, only hard decisions. A peaceful end to the Iranian nuclear problem should continue to be sought, but the countdown to a nuclear Iran has already begun.

Israel - at least for the moment - seems to be committed to a peaceful solution. But don't be surprised if Israel decides to jump the diplomatic track in an effort to end - or at least forestall - Iran's bid to become the first anti-Israeli member of the exclusive nuclear club.

Peter Brookes, a Heritage Foundation senior fellow, was in Indonesia to monitor the presidential election. E-mail:[email protected]