At a dinner party two weeks before the election, President Bush agreed that a second-term flashpoint would likely center around the acquisition of nuclear weapons by Iran.

“It is Israeli policy not to let that happen,” Mr. Bush said, adding after a moment’s pause. “Don’t go telling anyone I gave a green light.”

Mr. Bush has triangulated his position between newly rediscovered European allies and the Israeli ally. The Europeans’ fear of confrontation with Iran runs almost as deeply as the Israeli fear of a nuclear-armed Iran. The difference, of course, is that while Tehran’s long-range missiles can target southern European cities, they are more likely to be aimed, and deployed, at Israeli cities.

That explains Mr. Bush’s skeptical reaction to Iran’s acceptance of the deal proposed by England, France, and Germany. In contrast to the European sigh of relief, Mr. Bush said the deal was nice, if true. In contrast to both, Israelis shrugged off the idea Iran was dropping the development of nuclear weapons and missiles that can deliver them.

Faced with a possible Bush defeat, Tehran preferred to wait for what they hoped might be a more flexible Kerry administration.

The European powers told Iran that unless they could announce an agreement whereby Tehran suspended uranium enrichment, Europeans would join the Americans in referring the matter to the Security Council from the International Atomic Energy Agency, opening the way to the imposition of international sanctions.

That explains why the deal came after Mr. Bush’s re-election and before the November 25 meeting of the IAEA.

Ironically, the Iranian crisis has blunted somewhat the fallout concerning Mr. Bush’s failure to find weapons of mass destruction in Iraq. The entire West agrees that a militant, terrorist supporting Islamist state is now close to arming itself with nuclear weapons. The entire West agrees that this is, at the very least, undesirable, and, in the main, unacceptable.

In place of the distrust of Mr. Bush, even the confrontation-averse director general of the IAEA, Mohammed ElBaradei, acknowledges a “deficit of confidence” in Iranian protestations of peaceful intent.

Without any intention of diminishing their significance, note that the differences among the Western allies are tactical. The question is whether to leave a credible threat of the use of force on the table.

Not content with carrying this stick, the Europeans proposed a package of incentives, including (North Korea anyone?) a light-water reactor and “future economic benefits.”

In this regard, attention should be drawn to the report in the New York Times about the carrots dangled in front of Tehran. According to the Times, the Big Three of the European Union – England, France, and Germany – supported “a two-track approach, of engagement and confrontation” with Iran. Confrontation manifested itself in the threat to go the Security Council and impose sanctions.

Under the engagement category, the Europeans floated the idea if Iran improved its human rights record and scuttled its support for Islamic terrorism, it could receive “a role in the peace process between Israel and the Palestinians.”

Late last month at the Quai d’Orsay, I asked French Foreign Minster Michel Barnier what role Iran might play with regard to Israel, considering the regime’s opposition to Israel’s continued existence as a Jewish state.

Just back from a prolonged visit to Israel, Mr. Barnier told me that, like Libya, Iran had to be given “a chance to change.”

Anyway, he said, “Do you want to fight them?”

Similarly, the United Kingdom foreign minister, Jack Straw, said an American attack on Iranian facilities was “inconceivable.”

In Israel, it is a nuclear-armed Iran that is deemed “inconceivable.” Support for a military option crosses Israel’s notoriously divisive political spectrum. But Israel’s options are not limitless. For one thing, it is unclear how effective an Israeli strike would prove. Jerusalem must also consider that Tehran would order a counterstrike, first of all from the thousands of missiles Iran gave its Lebanese satellite, Hezbollah.

The missiles, deployed in Lebanese villages and refugee camps and aimed south at Israel, include rockets that put Haifa in range.

Iran could also stoke Shiite violence in Iraq.

December’s Atlantic Monthly report on a war game look at military options for Iran concludes that the next president “should understand that he cannot prudently order an attack on Iran. But his chances of negotiating his way out of the situation will be greater if the Iranians don’t know that.”

“If you say there is no acceptable military option, then you end any possibility that there will be a non-nuclear Iran,” said panelist David Kay. “If the Iranians believe they will not suffer any harm, they will go right ahead.”

That common sense conclusion runs afoul of the European decision to unilaterally remove the threat of force. Like a Greek tragedy, the attempt to prevent war could trigger precisely the result it sought to avoid.

Mr. Twersky is a contributing editor of The New York Sun.