R ightly, the international community is worried about Iran's nuclear enrichment activities. Though the Islamic Republic insists that it is only interested in nuclear technology for fuel, the United Nations' nuclear watchdog recently reported that Iran has blocked its attempts to investigate what appear to be various components of a nuclear weapons programme. The question is what the rest of the world should do about it.

The outgoing US President has been clear enough, at least in the past. He has repeatedly spoken of launching a military strike against the presumed nuclear facilities. He reiterated the idea this week on his farewell tour of Europe. In Germany, the Chancellor Angela Merkel made it clear that she did not share his inclination for the military option. She very clearly pinned her hopes on diplomatic efforts, she said, speaking for the rest of Europe, which has made it clear that air strikes on Iran are unthinkable.

Revealingly, George Bush is blowing hot and cold on the idea. He talked tough last week in Israel but in Slovenia this week his tone was more conciliatory. Three times he said that a diplomatic solution was his "first choice", though many detected in his words the default position that if diplomacy failed there were other options. He repeated his sinister insistence that "all options are on the table".

Iran's president, Mahmoud Ahmadinejad, openly mocked Mr Bush's stance, promising to continue to defy the international community with his nation's nuclear activities. If he is hoping to goad Mr Bush into an air-strike, it is easy to see why. A US bombing raid on Iranian reactors would allow him to launch a barrage of Silkworm missiles on tankers in the Strait of Hormuz and Arab oil facilities shutting down all oil exports from the Gulf. Some 17 million barrels of oil a day could come off world markets. It is just the kind of macho gesture which might save his skin in the Iranian presidential elections next year, in which he can otherwise expect a drubbing after so signally failing to deliver the economic reforms and improvements in Iranian standards of living which he promised at the last election.

Tomorrow, the European Union's foreign policy representative Javier Solana travels to Tehran with a mixed bag of incentives and sanctions which, he can suggest, will be imposed unilaterally by the EU, if not by the entire United Nations, if Iran does not suspend its uranium enrichment activities. That kind of simultaneous carrot and stick will be far more unnerving to Mr Ahmadinejad than the discredited US tactics of sabre-rattling.