This week´s furious row over US allegations of a link between the Saudi royal family and the terrorists of Saudi-born Osama bin Laden´s al-Qaida gang has highlighted a deep fault-line in the Bush administration´s "war on terror". Prince Bandar bin Sultan, the Saudi ambassador to Washington, says he is "outraged" by suggestions that charitable donations made by his wife may have ended up with two men allegedly associated with the September 11 hijackers. But that has not prevented some barbed US political attacks on the Saudi government, even before an FBI inquiry is concluded.

The Saudis have "played a duplicitous game", says US senator Charles Schumer, by effectively buying off terrorists and turning a blind eye to their activities. Richard Lugar, the incoming chairman of the senate foreign relations committee, says "disturbing issues" have been raised, and that the US must insist on a Saudi crackdown on terror financiers.

This is but the latest in a series of public spats that began after September 11, when the US discovered that 15 of the 19 hijackers were Saudis and that al-Qaida´s operations in Afghanistan, Pakistan and elsewhere appeared to have been financed with monies emanating from the desert kingdom.

American accusations of official or unofficial Saudi complicity in terrorism have ebbed and flowed ever since, usually channelled through the US media. After the Bali bombing, for instance, there were reports that a Saudi businessman helped finance the atrocity.

Even the august New York Times has joined in. "One of the disturbing realities clarified by last month´s attacks is Saudi Arabia´s tolerance for terrorism," the paper said in October last year. "With Riyadh´s acquiescence, money and manpower from Saudi Arabia helped create and sustain Osama bin Laden´s terrorist organisation." One well-known American columnist, reflecting a tide of anti-Saudi feeling, has even urged George Bush to invade Saudi Arabia and turn it into a giant US "self-serve gas pump".

The attacks on the Saudis often seemed to be based on US intelligence and other information leaked by American officials concerned that not enough is being done by their own government. Last summer, an explosive classified intelligence briefing to the Pentagon´s defence advisory board was surreptitiously made public.

"The Saudis are active at every level of the terror chain, from planners to financiers, from cadre to foot soldier, from ideologist to cheerleader," the report stated. It described the kingdom as "the kernel of evil, the prime mover, the most dangerous opponent" that the US faced anywhere in the Middle East. "Saudi Arabia supports out enemies and attacks our allies".

As the US defence secretary, Donald Rumsfeld, quickly pointed out at the time, the report did not reflect official US policy. Indeed, each flurry of anti-Saudi agitation in the US has usually been followed by placatory and conciliatory statements from the Bush administration.

Last autumn, Ari Fleischer, George Bush´s chief spokesman, said the president was "very pleased with the kingdom´s contributions" to the war on terror. This week, after the latest row, Fleischer repeated himself. "The president believes that Saudi Arabia has been a good partner," he said, although he added that it "can do more".

Earlier this year, Bush afforded Saudi Crown Prince Abdullah, the country´s de facto ruler, the signal honour of an invitation to his Texas ranch, and listened attentively to his ideas about a Palestinian-Israeli settlement. At one point last August, Bush assured Bin Sultan of the two countries´ "eternal friendship".

The US also downplays Saudi Arabia´s appalling human rights abuses, its lack of democratic freedoms and of a free press, and its denial of women´s rights - all key justifications, by the way, proffered for the US overthrow of the Taliban regime in Afghanistan.

Speaking during a visit to Mexico this week, the US secretary of state, Colin Powell, again went out of his way to coddle the Saudi princes. Concerns about terrorism, he said, should not lead the US "to the point where we rupture relations with a country that has been a good friend". This is actually quite amazing, if US reactions to other countries in similar circumstances are considered. If the state in question were Iran, for example, it would probably have been attacked by now.

This smacks of appeasement. So what is really going on here?

Why, in its ruthless pursuit of the September 11 murderers and their supporters - a chase that has encompassed most of the Middle East and south and south-east Asia - is the Bush administration so loath to confront the Saudis?

Why, if there is persuasive evidence of Saudi complicity in those and subsequent attacks, has stern action (such as sanctions or trade embargoes) not been taken, or at least formal, public diplomatic protests made?

Why indeed is the current focus of US military and diplomatic efforts on Baghdad, not Riyadh? Why, in other words, does Bush, not known for being a man who bites his lip when it comes to terrorism, look at the Saudis and turn the other cheek?

Well, the answer could be that all these anti-Saudi allegations are foul and unjustified calumnies for which there is not a shred of evidence. But if you believe that, you can stop reading right here (and maybe seek professional help).

Or it could be that, sad to say, the Bush administration is operating a double standard. It could be that the US government is only too aware of the Saudi terror connection, but is not prosecuting it vigorously on behalf of the September 11 victims and the American people because it has other priorities.

What might they be? One easy answer is oil. Saudi Arabia provides 17% of daily US oil needs and, more important in strategic terms, controls about 25% of global reserves. Despite attempts to diversify America´s supply, US dependence on Persian Gulf oil is projected to increase, not decrease, in the next 20 years.

All major production increases in that period are also expected to come in and around the Gulf; Saudi Arabia is the only producer with enough spare capacity to keep the world market stable and prevent price "spikes" in times of crisis. Without Saudi Arabia, it is no exaggeration to say the US economic motor could quickly conk out.

Another priority is Israel. Without US protection, military aid and financial backing, Israel´s very existence would be in continuing doubt. As it is, with the rulers of Saudi Arabia (and Egypt and Jordan) on America´s diplomatic team, the enmity of rejectionist Arabs and hardliners in Iran can be kept at bay and the illusion of a peace process maintained.

This also means that Israel´s current government, led by Bush friend and ally Ariel Sharon, can continue its repression of the Palestinians almost with impunity. This is why Bush listened politely to Abdullah´s peace plan in Texas (and then held out the prospect of a Palestinian state one distant day). The US needs to keep the Saudis sweet if a lid is to be kept on the intifada, and if Jewish interests, in Israel and the US, are to be maintained.

Another priority is Iraq. The US has large military bases in Saudi Arabia and will want to use them in any attack on Iraq. Whether or not it gets permission to do so, it still needs to keep the Saudis on board during a war. If the Saudis, guardians of Mecca and the holy shrines and the heartland of Islam, made a stand against war, the peoples of the whole Gulf region and Egypt and Jordan might follow in opposing the US and its allies. It would not just be a military logistics problem then.

Like Bush, the Saudis have a score to settle with Saddam Hussein. They fear him for what he did in 1990 and might, one day, do again. They want him gone. And let us not forget: Iraq´s oil is important, too. It has 11% of known world reserves and (even now) the US continues to be the biggest single purchaser of Iraqi oil. The US and Saudi governments have a shared economic interest in, shall we say, regulating that supply. The US will also need help in paying for any war and subsequent occupation.

There are other reasons, too, for the Bush administration´s appeasement of the Saudis. One is the concern that the weak Saudi monarchy, while objectionable in many ways, could be replaced by something far worse - such as an Islamist fundamentalist regime of the type that seized power in Iran in 1979. Better the devil you know, as they say in Christendom, than the devil you don´t.

So, for the sake of all of the above, it appears that - when it comes to Saudi Arabia - the Bush administration is fighting its "war on terror" with its right hand tied behind its back, its left eye closed, and shackles round its ankles. But those constraints are entirely self-imposed. It is for the American people to judge whether this is a wise or honourable policy and whether, in Bush´s endlessly repeated phrase, it truly serves "freedom´s cause". (Guardian Unlimited © Guardian Newspapers Limited 2002 11/28/02)