Esquire magazine's recent description of Admiral William Fallon as "the man between peace and war" seems a little unfortunate in the light of his resignation this week as head of US Central Command. It is especially so, considering that the article to which this description was attached is being cited as the reason Admiral Fallon had to step down.

The official explanation for his resignation is that there was a damaging "perception problem" of a difference of opinion between Fallon and the White House. On the contrary, this departure was all about substance. It was an open secret in US military circles that the admiral disagreed with the Bush administration's strategy in the Middle East. He was against the troop "surge" in Iraq and wanted to give military priority to Afghanistan and Pakistan instead. In particular, he disagreed with the administration's bellicose attitude towards Iran. The White House is at pains to argue that the military option with regard to Iran remains "on the table", despite the release last year of a US National Intelligence Estimate report stating that Tehran is no longer pursuing a nuclear weapon. Yet Admiral Fallon had this to say last autumn on Iran to the Arabic broadcaster Al-Jazeera: "This constant drumbeat of conflict is not helpful or useful. I expect that there will be no war, and that is what we ought to be working for." A more obvious rebuff to his political masters could scarcely have been conceived.

Admiral Fallon is quite right about the self-defeating policies of the Bush administration. Iraq has indeed been a dangerous distraction from Afghanistan and Pakistan. With regard to Iran, it is true that, as the US Defence Secretary Robert Gates pointed out this week, an American attack on the country's nuclear sites is most unlikely in the wake of the NIE report. But although the White House may not be about to order an assault, the administration's hard line on Tehran is certainly impeding progress to regional stability.

Admiral Fallon is not the first to fail to persuade the White House to adopt a more constructive approach to Iran. The 2006 Iraq Study Group recommended bringing neighbouring states, including Iran, on board to improve the security situation in the country. Yet despite commissioning the report, Mr Bush did exactly the opposite, seeking to isolate Iran and ordering the surge into Baghdad.

What lies behind this refusal to engage? After so many years of policy failure and repeated rejections of informed advice, it is impossible not to conclude that the root of the administration's resistance is a simple, stubborn, ideological rigidity. It is a rigidity for which the region has paid a catastrophic price.