It is scarcely surprising that the Iranian government believes that the United States is behind the kidnapping of one of its diplomats in Baghdad on Sunday. The Iranians say he was seized by 30 uniformed men from an Iraqi army commando battalion that often works with the US military services in Iraq.
The US had already shown its contempt for any diplomatic immunity protecting Iranians in Iraq by arresting five officials in a long-established Iranian office in the Kurdish city of Arbil last month. The White House had earlier authorised US forces to kill or capture Iranians deemed to be a threat.
It is striking how swiftly Washington is seeking to escalate its confrontation with Iran. Its rhetoric has returned to the strident tone so often heard when the US was accusing Saddam Hussein in 2002 and 2003 of hiding weapons of mass destruction that threatened the world.
No serious observer of Iraq since the US invasion believes for a moment that Iran has sustained the Sunni insurgency or played an essential role in the rise of the Shia militias. It was obvious that when Saddam fell Iran would benefit. He was, after all, the arch enemy of Tehran, and the Iranians were delighted to see him go.
A second inevitable consequence of the end of Saddam's predominantly Sunni regime was that the Iraqi Shia, 60 per cent of the population, would take power in Baghdad. Foreseeing and wishing to avoid just such an outcome, President George Bush senior refused to send the US Army to Baghdad after his victory in Kuwait in 1991.
What does Mr Bush hope to achieve by confronting and possibly even going to war with Iran? Within Iraq it is a policy of great foolishness, because it will be seen as being anti-Shia as well as anti-Iranian. The Iraqi Shia are suspicious that the US is planning to rob them of power. Since last year, for the first time, a majority of the Shia support armed attacks on US-led forces.
There are some benefits for Washington in escalating the conflict with Iran. The Bush administration has specialised in creating demons responsible for all the ills of Iraq. First there was Saddam Hussein and then Abu Musab al-Zarqawi. Both were killed last year, but the war has continued to escalate.
Iran is now being promoted as the new demon. It is supposedly behind the provision of roadside bombs that have killed so many US and British troops - though the technology involved in these simple but deadly devices could generally be found in a garden shed.
Iraq has long been short of everything except weapons. Every Iraqi family possessed arms even under Saddam Hussein. In the early 1990s he introduced a buy-back programme by which he would pay for heavy weapons handed in. One tribe in south-east Iraq turned up with three tanks which they offered to sell to the government if the price was right. Deeming the official offer too low, they returned the tanks to their tribal arsenal.
It will be very difficult for the US to pursue an anti-Iranian policy in Iraq and the Middle East while supporting a pro-Iranian Shia government in Baghdad. Strangely, the only powerful party that is as vociferously anti-Iranian as Mr Bush is the Baath party. It has for long justified its opposition to the takeover of government by the Shia majority by pretending they are Iranian pawns.
In the Middle East as a whole, the new US anti-Iranian policy has more to recommend it from an American point of view. There is plenty of anti-Iranian and anti-Shia sentiment around. Sunni Arab leaders in Saudi Arabia, Egypt and Jordan were embarrassed by the success of the Shia Hizbollah in the war in Lebanon last summer, compared to their own supine incompetence. Little wonder they are happy to join the US in whipping up feeling against the Shia and the Iranians.
Mr Bush is acting rather like cynical Tory politicians at the end of the 19th and the beginning of the 20th centuries who played "the Orange Card" over Ulster. Claiming to be safeguarding the empire, they stirred anti-Catholic and anti-Irish bigotry to their own political advantage. Mr Bush may reap similar benefits by playing the anti-Shia and anti- Iranian card.
One expert on Iraq asked me in perplexity: "Even if Bush does launch a war against Iran, where does he think it will get him? He will still be stuck in Iraq and the Iranians are not going to surrender. He will just have widened the war."
The answer to this question is probably that the anti-Iranian tilt of the Bush administration has more to do with American than Iraqi politics. A fresh demon is being presented to the US voter. Iran is portrayed as the hidden hand behind US failure in both Iraq and in Lebanon. The US media, gullible over WMD, is showing itself equally gullible over this exaggerated Iranian threat.
The Bush administration has always shown itself more interested in holding power in Washington than in Baghdad. Whatever its failures on the battlefield, the Republicans were able to retain the presidency and both Houses of Congress in 2004. Confrontation with Iran, diverting attention from the fiasco in Iraq, may be their best chance of holding the White House in 2008.
The writer is the author of 'The Occupation: War and Resistance in Iraq' published by Verso