Shortly after President Bush announced the attack on Iraq -- and shortly after the world's major financial exchanges began to open -- the United States and other Western countries moved to guarantee energy supplies to the free world by announcing they would release oil from their strategic petroleum reserves.

Soon, seven of the United States's largest oil companies took steps to freeze prices at the pump.

Earlier, central banks in the United States and Japan had made it clear they would supply nearly unlimited amounts of cash to banks and traders in the event of war.

And 36 hours before shooting broke out, federal commodity regulators passed an emergency rule enabling the New York Mercantile Exchange (Nymex), the focal point for setting world oil prices, to temporarily halt trading if prices moved too quickly, up or down.

There was even a plan to close stock or commodity exchanges for half an hour to give investors time to incorporate information about the war into their investment strategy.

All in all, the efforts by government regulators here and abroad to calm financial market jitters in a crisis situation have been unprecedented. The goal was to keep consumers and investors alike from panicking in a wartime market sure to be heavy in trading and price swings.

And when the fighting actually began Wednesday evening, stock prices soared, interest rates tumbled and crude oil prices fell in their biggest one-day drop in history -- but, by all accounts, in orderly fashion. Was it the result of good planning, or simply that one fact overshadowed all others: The first day of war went in the allies' favor?

"The preparations were never really tested, so we really don't have an answer on how much they affected the market," said Michael P. Andrews, a director in the Washington office of Salomon Brothers Inc.

"It was the success of the military campaign so far that created the psychological rally. And this was a psychological rally."

"Basically we didn't have to be tested because the initial attack went well," said Richard G. Ketchum, head of the Securities and Exchange Commission's division of market regulation. "Up markets tend to be more orderly."

Nonetheless, he said, "I think the concerns over a market panic {would have been} legitimate if the news had not been so good or so clear or if people had not had so long to absorb the news before they started to trade."

Last night, government officials were bracing for just such a change in the mood of the markets following the Iraqi missile attack on Israel, but they emphasized they still expected the markets to open on time. They noted, however, that decisions could be affected by what happened overnight in the Middle East and in Asian and European markets.

Market officials and federal regulators spent months preparing for the worst only to find that on the first day of the conflict it was good news, rather than bad, that tripped a key element of their preparedness plan: circuit breakers.

These temporary halts in trading, designed to dampen wide price swings, were set off at various times during the day on the New York Stock Exchange and on the New York and Chicago commodity exchanges.

"I think that overall our preparedness program ... contributed to greater confidence, to a feeling that whatever is humanly possible to do has been done," said Robert R. Davis, senior vice present of the Nymex and a former commissioner of the Commodities Futures Trading Commission (CFTC).

"Even with those extreme price movements, we had a very orderly trading day. With a war, there could have been chaos. In terms of financial risk, it doesn't matter if the market is moving up or down. The point is to have an orderly planning environment."

Regulators put on a relaxed face, hopeful it would become a self-fulfilling prophesy.

"We have vast experience in monitoring volatile markets," CFTC Chairman Wendy Gramm said minutes before the start of oil trading in New York yesterday. As it was, closer-than-usual monitoring yielded few if any surprises or major concerns, a CFTC spokesman said.

At the Department of Energy, which lacks statutory authority to set prices or allocate oil supplies, months were spent jawboning the industry and consumers to fend off panic buying that would drive up prices or create shortages during war.In the week before the war started, DOE officials talked with oil company executives, the Saudis, officials of the Nymex and state regulators, as well as the press, to get out the word that oil was plentiful and was likely to remain plentiful, war or not. The message to buyers was: Don't panic and don't hoard. The message to oil companies was: Don't gouge the public on prices.

Something -- either that or news of success on the first day of war -- worked.

"We are doing everything we can to allay fears not only in the American public but those throughout the world, that their economies need not be destroyed by a conflict such as we are engaged in," Energy Secretary James Watkins said yesterday. "I think we've done that."

He said he did not ask the oil companies to freeze or reduce prices, as several announced they would, but acknowledged that "we have talked to them" and that the companies are "very sensitive" to possible criticism for the large profits they are expected to report for the last three months of 1990.

Watkins, asked how much of yesterday's orderly markets should be attributed to pre-planning and how much to military prowess, was more bullish than other government regulators about their role.

"Fifty-fifty," he said.