Leading article: Barack Obama must hold his nerve on Iran

There are many alarming aspects to the escalating tension over Iran's nuclear programme. But perhaps the most worrying of all is that every pressure on Barack Obama – be it political, economic, or, most of all, electoral – is pushing him to take a hard line. He must resist.

This week's fractious talks between the US President and his Israeli counterpart have only added to the strain. Mr Obama attempted to set a temperate tone: blending the assurance that the US will "always have Israel's back" with a much-needed warning about the dangers of too much "loose talk" of military conflict.

Benjamin Netanyahu showed little sign of softening his bellicose stance, however. "I will never let my people live under the shadow of annihilation," the Israeli Prime Minister told his US audience, adding a darkly emotive comparison with US unwillingness to bomb the Nazi death camp at Auschwitz.

It is not that Israel's concerns about Iran are unjustified, or that it has no right to defend its interests. And with Iran rapidly shifting its enrichment facilities into heavily fortified bunkers beyond the reach of Israeli weapons, Mr Netanyahu's assertion that "none of us can afford to wait much longer" is an understandable one.

Nonetheless, both sense and feeling argue in the strongest possible terms against an attack on Iran. Not only would such a move achieve little, setting Tehran's nuclear ambitions back by perhaps two years at best. The cost – in terms of loss of life, of diplomatic relations soured for a generation, and of the potential for wider geopolitical catastrophe – is simply too high.

Neither should Mr Obama's resistance be restricted to the subject of an immediate strike. Mr Netanyahu wants the US to draw a "red line" – which, once crossed, would trigger instant military intervention – at Tehran's acquiring the capacity to build a bomb. So far, Mr Obama has maintained his position, insisting that the red line is not the capability but the construction. But the pressure on him to give ground will only increase.

Such strained relations with Israel would be tricky for a US president at any time. In an election year, they become egregious indeed. To appreciate the risks, one need look no further than the otherwise-lacklustre Republican candidates' efforts to characterise Mr Obama as soft on Iran. But it is not only the exigencies of the relationship with Israel which are putting the President's Iran strategy under the microscope.

With oil prices up by more than 10 per cent thanks to uncertainties over sanctions on Tehran, there is also the drag on America's burgeoning economic recovery. Even worse, petrol prices nudging up towards $4 per gallon are electoral poison in the land of the sports utility vehicle. The President is right to counter calls for military action against Iran with the observation that the sanctions programme is yet to fully bite. He will have to stand firm even as the effects of the strategy are felt at home.

Sanctions are not everything, however. For all the mutual distrust, diplomatic efforts are yet to be exhausted. And it is here that Mr Obama must direct his energies.

There has been real progress. Last month saw international nuclear inspectors allowed into Iran for the first time in three years, and, after a rather patchy start, they are now to gain some access to the controversial military site at Parchin. Meanwhile, Tehran's offer to resume nuclear talks with the West has been accepted.

Given Iran's long history of playing for time, it would be naïve to expect too much. But with so much at stake, it would be irresponsible not to make the most of any opportunities for an amicable solution. Election or no election, Mr Obama's primary responsibility must be to avoid a war.