"The Saudis are very happy with oil at $55 per barrel, but they're also nervous," a Western diplomat in Riyadh told me in May, referring to the price that prevailed then. (Like all the diplomats I spoke to, he insisted on speaking anonymously because of the sensitivities of relations with Saudi Arabia.) "They don't know where this magic line has moved to. Is it now $65? Is it $75? Is it $80? They don't want to find out, because if you did have oil move that far north . . . the chain reaction can come back to a price collapse again."

High prices can have another unfortunate effect for producers. When crude costs $10 a barrel or even $30 a barrel, alternative fuels are prohibitively expensive. For example, Canada has vast amounts of tar sands that can be rendered into heavy oil, but the cost of doing so is quite high. Yet those tar sands and other alternatives, like bioethanol, hydrogen fuel cells and liquid fuel from natural gas or coal, become economically viable as the going rate for a barrel rises past, say, $40 or more, especially if consuming governments choose to offer their own incentives or subsidies. So even if high prices don't cause a recession, the Saudis risk losing market share to rivals into whose nonfundamentalist hands Americans would much prefer to channel their energy dollars. A concerted push for greater energy conservation in the United States, which consumes one-quarter of the world's oil (mostly to fuel our cars, as gasoline), would hurt producing nations, too. Basically, any significant reduction in the demand for oil would be ruinous for OPEC members, who have little to offer the world but oil; if a substitute can be found, their future is bleak. Another Western diplomat explained the problem facing the Saudis: "You want to have the price as high as possible without sending the consuming nations into a recession and at the same time not have the price so high that it encourages alternative technologies."

From the American standpoint, one argument in favor of conservation and a switch to alternative fuels is that by limiting oil imports, the United States and its Western allies would reduce their dependence on a potentially unstable region. (In fact, in an effort to offset the risks of relying on the Saudis, America's top oil suppliers are Canada and Mexico.) In addition, sending less money to Saudi Arabia would mean less money in the hands of a regime that has spent the past few decades doling out huge amounts of its oil revenue to mosques, madrassas and other institutions that have fanned the fires of Islamic radicalism. The oil money has been dispensed not just by the Saudi royal family but by private individuals who benefited from the oil boom -- like Osama bin Laden, whose ample funds, probably eroded now, came from his father, a construction magnate. Without its oil windfall, Saudi Arabia would have had a hard time financing radical Islamists across the globe.

For the Saudis, the political ramifications of reduced demand for its oil would not be negligible. The royal family has amassed vast personal wealth from the country's oil revenues. If, suddenly, Saudis became aware that the royal family had also failed to protect the value of the country's treasured resource, the response could be severe. The mere admission that Saudi reserves are not as impressively inexhaustible as the royal family has claimed could lead to hard questions about why the country, and the world, had been misled. With the death earlier this month of the long-ailing King Fahd, the royal family is undergoing another period of scrutiny; the new king, Abdullah, is in his 80's, and the crown prince, his half-brother Sultan, is in his 70's, so the issue of generational change remains to be settled. As long as the country is swimming in petro-dollars -- even as it is paying off debt accrued during its lean years -- everyone is relatively happy, but that can change. One diplomat I spoke to recalled a comment from Sheik Ahmed Zaki Yamani, the larger-than-life Saudi oil minister during the 1970's: "The Stone Age didn't end for lack of stone, and the oil age will end long before the world runs out of oil." Until now, the Saudis had an excess of production capacity that allowed them, when necessary, to flood the market to drive prices down. They did that in 1990, when the Iraqi invasion of Kuwait eliminated not only Kuwait's supply of oil but also Iraq's. The Saudis functioned, as they always had, as the central bank of oil, releasing supply to the market when it was needed and withdrawing supply to keep prices from going lower than the cartel would have liked. In other words, they controlled not only the price of oil but their own destiny as well.

"That is what the world has called on them to do before -- turn on the taps to produce more and get prices down," a senior Western diplomat in Riyadh told me recently. "Decreasing prices used to keep out alternative fuels. I don't see how they're able to do that anymore. This is a huge change, and it is a big step in the move to whatever is coming next. That's what's really happening."

Without the ability to flood the markets with oil, the Saudis are resorting to flooding the market with promises; it is a sort of petro-jawboning. That's why Ali al-Naimi, the oil minister, told his Washington audience that Saudi Arabia has embarked on a crash program to raise its capacity to 12.5 million barrels a day by 2009 and even higher in the years after that. Naimi is not unlike a factory manager who needs to promise the moon to his valuable clients, for fear of losing or alarming them. He has no choice. The moment he says anything bracing, the touchy energy markets will probably panic, pushing prices even higher and thereby hastening the onset of recession, a switch to alternative fuels or new conservation efforts -- or all three. Just a few words of honest caution could move the markets; Naimi's speeches are followed nearly as closely in the financial world as those of Alan Greenspan.

I journeyed to Saudi Arabia to interview Naimi and other senior officials, to get as far beyond their prepared remarks as might be possible. Although I was allowed to see Ras Tanura, my interview requests were denied. I was invited to visit Aramco's oil museum in Dhahran, but that is something a Saudi schoolchild can do on a field trip. It was a "show but don't tell" policy. I was able to speak about production issues only with Ibrahim al-Muhanna, the oil ministry spokesman, who reluctantly met me over coffee in the lobby of my hotel in Riyadh. He defended Saudi Arabia's refusal to share more data, noting that the Saudis are no different from most oil producers.