The way in which the growing confrontation with Iran is being sold by the US, Israel and West European leaders is deeply dishonest. The manipulation of the media and public opinion through systematic threat exaggeration is similar to the drum beat of propaganda and disinformation about Iraq's non-existent weapons of mass destruction that preceded the invasion in 2003.

The supposed aim of imposing sanctions on Iran's oil exports and central bank, measures officially joined by the EU, is to force Iran to abandon its nuclear programme before it reaches the point where it could theoretically build a nuclear bomb. Even Israel now agrees that Iran has not yet decided to do so, but the Iranian nuclear programme is still being presented as a danger to Israel and the rest of the world.

There are two other menacing parallels between the run-up to the Iraq war and what is happening now. The purported issue is the future of the Iranian nuclear programme, but, for part of the coalition mustering against Iran, the real purpose is the overthrow of the Iranian government. The origin of the present crisis was the moves last November and December by the neoconservatives in the US, Benjamin Netanyahu's Likud Party and the Israel lobby in Washington to impose sanctions on Iranian oil exports and Iran's central bank. These are very much the same people who targeted Iraq in the 1990s. They have been able to force the White House to adopt their programme and it is now, in turn, being implemented by a European Union that naively sees sanctions as an alternative to military conflict.

In reality, sanctions are likely to intensify the crisis, impoverish ordinary Iranians and psychologically prepare the ground for war because of the demonisation of Iran. The problem is that Israel and its right-wing American allies are more interested in regime change than Tehran's nuclear programme. The Israeli newspaper Haaretz succinctly stated the differences between the Israeli government and Washington. It said that "while the Americans are actively seeking a way to start a dialogue, Israel is preaching confrontation and the toppling of the government in Tehran".

It is this latter policy that has triumphed. Israel, its congressional allies and the neoconservatives have successfully bamboozled the Obama administration into a set of policies that make sense only if the aim is overthrow of the regime in Tehran. The Iranian government has been given no diplomatic way to climb down without humiliation. Its nuclear programme has been turned into a symbol of resistance to foreign diktats. This makes it impossible for anybody in the fractious Iranian leadership to compromise without being denounced as a traitor by political opponents.

Whatever the intentions of Barack Obama when he was elected, the covert offensive initiated by President Bush against Iran has continued. He signed a secret "presidential finding" in 2008 under which $400m was allocated to fund Iranian government opponents. The US's new allies included unsavoury groups such as the Sunni sectarian killers of Jundullah operating in Iranian Baluchistan. The US may have intended to limit the degree of co-operation but, according to Foreign Policy magazine, Mossad agents simply posed as CIA members in dealing with Jundullah. What was the point of these pinprick attacks? A few bombs in Iranian Baluchistan are not going to pose much of a threat to the Iranian leadership in Tehran. The motive was most probably to provoke the Iranians into retaliation against the US which would bring a US-Iranian military conflict closer.

The same may well be true of the assassinations of Iranian nuclear scientists. A little-noticed aspect of these is that the scientists were easy to kill because they were driving themselves around Tehran in their own cars. But any country that has evidence its top scientists are at risk provides them with security. The lack of the simplest security measures argues that these scientists were never at the centre of Iran's nuclear programme. A more likely explanation for the attacks, assuming that Israel was behind them, was to provoke Iran into a retaliation against the US or Israel that would be a casus belli.

It is difficult not to admire the skill with which Mr Netanyahu has manoeuvred the White House and European leaders into the very confrontation with Iran they wanted to avoid. He has been helped by the Iranian President's anti-Semitic outbursts and the apparent fixing of the 2009 presidential election. But Mr Netanyahu's most effective weapon has been the threat that Israel would unilaterally launch air strikes unless the White House did something. This has always been less likely than it looked. Israel has seldom gone to war without a "green light" from the US.

A more rational explanation of Israeli threats to act alone is that they were wholly designed to scare the White House and its European allies. The Israeli Defence Minister, Ehud Barak, made blood-curdling speeches about the imminence of the Iranian threat leaving Israel with no option but to launch a pre-emptive strike (until he quite recently said the opposite). The former head of Mossad gave credibility to unilateral Israeli action by warning that it would be a self-inflicted disaster for his country.

These manoeuvres succeeded. Serious sanctions are being imposed. Iran will have difficulty selling its oil. Its status as a regional power in the Middle East is weakening as the long-term survival of Bashar al-Assad, its most important ally, looks dubious.