There were once three rich, sparsely populated nations. Their wealth was unearned: It came from oil. Oil was selling at unheard-of prices and the sky seemed the limit.
With its money, Saudi Arabia began building a modern nation for its nomadic people, acquiring two up-to-date armies and projecting itself as leader of the Arab world.
With its money, Kuwait invested abroad, keeping its aims modest, hoping to retire to the comfortable rentier life in the 21st century.
With its money, Libya upgraded living standards, amassed an arsenal, and began promoting abroad the eccentric ideology of Col. Muammar Qaddafi.
That was in the oil-rich Middle East of the last 10 years. Ten years of petrodollar boom. But with the boom going bust, these oil states are having to readjust their lifestyles.
Saudi Arabia: The fabled ''oil-rich desert kingdom'' is going to have to slow its massive development effort. Current projections show the $91 billion annual spending program is putting the budget heavily in the red and the government will have to draw down central bank reserves.
World demand for Saudi Arabia's one noted export - oil - is flagging. Slow sales, plus a desire to save the Organization of Petroleum Exporting Countries (OPEC), has caused the kingdom to cut back oil production to 4.5 million barrels per day. At $34 per barrel, the current OPEC marker price, the Saudis need to pump at least 6 million barrels per day (b.p.d.) just to break even. Two years ago the Saudis were at 12 million b.p.d.
And the price of oil, economists reckon, is on the verge of dropping to $30 per barrel and below. Depending on how fast and how far the price drops, the Saudis can make adjustments. (Qatar and the United Arab Emirates, neighbors in the Gulf who are closely allied to the kingdom, are having similar problems.)
Already the Saudis have begun calling in some of the estimated $150 billion they have in reserve in European and American banks. Another measure taken has been to guarantee future oil markets by installing a system whereby preference in granting contracts and import licenses is given to businessmen from countries buying Saudi crude.
In the long run, however, the Saudis are going to have to cut back their appetite for development and imports. Economists say the kingdom will have to scale down ''downstream'' projects such as new metal and petrochemical plants, decrease military spending, perhaps deport foreign laborers, and curtail social services.
An economist close to the royal family says the budget contains much fat that can be trimmed. He says King Fahd can order austerity measures and government will comply.
But other economists say Saudi leadership will be unable to rationalize the economy so easily. Problems may occur, they say, in reducing expenditures for the two-army military (a uniquely Saudi loyalty insurance).
Cutting social services could make the high-spending ways of the 5,000 Saudi princes much more conspicuous. As a British diplomat in the Gulf says: ''To be poor in a rich country makes you notice your poverty.'' Memories persist of riots among lower-income Shiites in 1979.
Less Saudi money also means less Saudi prestige in the Middle East. The billions that go each year to help Iraq in its continuing war with Iran will be difficult to decrease, economists say, especially if Iran renews its 1982 offensive. Syria has been known to extort Saudi money for itself by threatening trouble or war with Jordan (as it did in December 1980).
So the Saudis may have to cut back subventions to more like-minded allies such as Jordan and Morocco. As a consequence, Saudi standing as friend and patron of moderates in the Middle East may be threatened.
Kuwait: This prudent city-state has for the past decade worked under the assumption that lean years might follow plenty. Kuwait kept spending moderate and invested abroad.
Last April, in fact, Kuwaitis tripled the price of gasoline at their own pumps to discourage consumption. Under the guidance of Amir Jaber, since his days as finance minister in the 1960s, Kuwaiti investment consortia have socked money away in Europe and America. By law 10 percent of Kuwait's oil revenues must be transferred to the Reserve Fund for Future Generations. (Belatedly, the UAE, Qatar, and Saudi Arabia are doing this, too.)
In 1982, for the first time, income from foreign assets exceeded oil earnings. Oil brought in an estimated $10 billion, though Kuwait pumped only half its preferred 1.5 million b.p.d. level. A diplomat in Kuwait notes: ''They may have to draw down their reserves, but Kuwait should be very comfortable.''
Amir Jaber is also directing Kuwaiti investments toward shares in European and American refineries, so that in an era of surplus oil Kuwait's unpopular heavy crude will have a continuing outlet.
Despite moderation at home, the Kuwaitis are subject to pressure from next door. Since 1981 Kuwait has made $6 to $8 billion in interest-free loans to Iraq - loans everyone admits will never be repaid - and more are wanted.
As a condition of ending the Gulf war, moreover, Iran has demanded huge reparation payments, which almost certainly could not be made by Iraq alone. Kuwait and Saudi Arabia would have to help.
Though the emirate has been wise with its oil wealth, it will still find it tough, living in the neighborhood it does.
Libya: There is less talk about exporting revolution from Tripoli today. There is also less money.
Much time is spent, instead, trying to enforce strict austerity measures and to hustle oil contracts and barter deals. In 1980, Libya pulled in more than $22 billion in oil revenue. In 1982, the figure did not exceed $10 billion, even though Libya (one of the ''production maximizers'' that have helped undermine OPEC) has pumped more than twice its OPEC quota and given discounts of up to $4 per barrel.
Because of the authoritarian nature of the Libyan regime, the decision to impose austerity was made with dispatch. Imports were simply cut to a trickle, leaving supermarket shelves barely stocked.
Next: the dilemma of the Iran-Iraq war.