It is a speech that even before its delivery today has split Israel and the Jewish community in America, and is being presented by the Obama team as crude electioneering and provocative mischief-making on the part of Mr Netanyahu.

Yet it is a necessary speech. All the signs are that the US, flanked by five other powers including Britain, is accelerating towards a deal with Tehran that will allow it to retain significant capacity to enrich uranium. The arrangement would in theory allow the West to spot and block one year in advance any attempt to build a bomb. That presumes easy access to the most sensitive nuclear sites and a quick and efficient verification system.

Israel does not trust Iran. It sees a regime that is so desperate to have sanctions lifted it is willing to fabricate concessions. The negotiations do not include Iran’s ballistic-missile programme, whose prime function can only be the delivery of a bomb.

Mr Netanyahu therefore comes to Washington full of suspicion not only about Iranian intentions but also those of the Obama administration. He fears the nuclear treaty would be the first step towards projecting Tehran as a de facto ally and a regional power-broker. A nation that is so often challenged by Iranian-backed Hezbollah militias and the Iranian-supplied weaponry of Hamas has a right to be concerned.

Read the editorial in full at The Times.