Not a week goes by before another embattled Israeli or American politician prods the dispute over Iran's nuclear programme. And every week this tactic - all stick, no carrot - fails to deliver any progress to bring a peaceful end to the standoff.

The latest example of the Americans jumping through hoops to please their Israeli allies came on Wednesday. US Defense Secretary Leon Panetta visited political and military leaders in Tel Aviv to reiterate Washington's view that while economic sanctions remain in place, they will not be on the table forever. A military strike, Mr Panetta emphasised, remains a real possibility.

The statement followed the gaffe-ridden junket this week by Republican candidate Mitt Romney, who essentially gave Israel a blank cheque of American support for aggression, not to mention its persecution of Palestinians. But Mr Panetta actually holds public office, and his words represent a commitment from the Pentagon.

His visit to Israel also coincided with another round of sanctions passed by the US Congress this week that will no doubt bring comfort to Israel's hawks. At present, the US build-up of military hardware in the region, and Israel's constant sabre rattling, are the loudest voices in the room - no mean feat, given Tehran's own propensity towards belligerent threats.

The most striking feature of this approach is that the bluster dooms diplomacy to irrelevance. Even if Tehran were interested in a diplomatic resolution, why would it negotiate with no mutual guarantees? Israel's hostility towards Iran (admittedly, a two-way street) will not go away regardless of the nuclear issue. Agreement without clear gains - the relaxing of sanctions, for instance, or a plan that allows Iran to realise its Nuclear Non-Proliferation Treaty rights - would be a failure for the Supreme Leader Ayatollah Ali Khamenei. Tehran's domestic politics will not allow him to back down under those circumstances.

Sanctions are biting. Iranian consumers are feeling the pinch in basic commodities, most famously in the price of chicken in recent weeks, but the military is also affected. A recent report by the International Institute for Strategic Studies, a London-based think tank, found that sanctions were significantly disrupting Iran's ballistic missile programme. There are serious doubts whether Iranian scientists can produce weapons-grade uranium in any case.

Iran does represent a serious threat to the region, but the wise plan is to pull it back from war, not push it further towards it. US and Israeli politicians are used to fist-pumping braggadocio that is popular at home. Washington, at least, should avoid this trap. It makes little sense to threaten first, and feign interest in dialogue later.