For the first time in this century, the nation has committed troops and other resources for an economic objective: the assurance of vital oil supplies from Saudi Arabia. Some observers fret that this goal is somehow sordid, not compatible with the high principles that President Bush said motivated our action.

It's true that Saudi Arabia is not a democracy teetering on the brink but an elitist monarchy exercising feudal powers. And America has looked the other way at times, when it could have defended human rights against aggressors as ugly as Saddam Hussein.

That represents a flaw in our national character. And it will be hard to live down the shame of the Reagan administration's willingness to tolerate Saddam's use of chemical weapons against the Iranians, and against some of his own people, the Kurds. Until recently, the Bush administration was still trying to curry favor with Saddam with agricultural subsidies and other bribes, ignoring his anti-democratic behavior.

But failure to have taken a stand against Saddam after he gobbled up Kuwait would only have been a compounding of those terrible mistakes -- and a form of national suicide. There is nothing evil about protecting our oil supply: Saddam, unchallenged, would control the Persian Gulf, therefore 50 percent of the world's oil reserves. He also would have had a clear shot at exterminating Israel, the one democratic country in the Middle East.

As high-level government officials tried to sift through the multiple consequences of a probable long-term confrontation with Saddam, one fact stands out:

The United States is a hostage to twin imports -- oil and capital to finance the budget deficit. Until the nation comes to grips with both dependencies, it will be at risk in both geopolitical and economic terms. At best, we are on the brink of a mild recession. At worst, we face a period of deep economic pain accompanied by great instability of markets.

That means that the nation must develop what it has resisted for the past 20 years -- an intelligent energy policy designed to cope with excessive dependence on Persian Gulf oil. It must also get control over the federal budget deficit, which in the wake of Saddam's aggression threatens to balloon to $300 billion in fiscal 1991, counting the real costs of the S&L bailout. The bigger deficit stems from reduced savings in the defense side of the budget: The peace dividend has gone to war. And recession means greater outlays for unemployment compensation while taxable income diminishes.

Parallel with the budget ''summit'' process, administration intelligence officials last week were told by outside experts that a new ''energy summit'' needs to be convened to consider a whole range of actions covering conservation of, and substitution for oil.

There is no excuse, for example, for lower mileage standards for cars. After oil prices drifted down in the late '80s, Detroit's passion for profit-packed gas-guzzlers led to erosion of strict minimum-mileage requirements. The result is that Japan once again will likely take advantage of more flexible manufacturing processes to concentrate on gas-economical vehicles. (In light of recent events, does anybody still want to nominate Japan as America's biggest potential enemy?)

The outside experts differ widely on whether the global embargo of Iraq will come apart like earlier efforts, such as the effort to isolate Rhodesia.

Those who fear the embargo will not put a serious strain on Saddam point out that as food shortages develop, he will make sure the Kuwaitis and Kurds suffer most, and will use their plight to try to generate public sympathy. The tactic could help weaken the resolve of embargo participants to hang tough.

Those who feel there's a chance the economic noose will work cite reports that the Iraqi dictator may not have been prepared for the global reaction. One sign: he left some of Iraq's foreign-exchange resources abroad. He almost certainly did not expect the immediate embargo by the Soviet Union and China on arms shipments.

One knotty problem on the energy front is whether to offset the loss of Iraqi and Kuwaiti oil by drawing down, at once, some of the 600 million barrels prudently accumulated over the years in the Strategic Petroleum Reserve. Bush administration officials have not made the move to tap the SPR, fearing a backlash from domestic oil producers who might regard it as a way of manipulating prices.

But Sen. Bill Bradley (D-N.J.), who persistently pressured the Department of Energy to fill the SPR as quickly as possible, suggests that tapping the reserve for 2 million barrels a day would help check oil-industry profiteers. They shamelessly pushed retail prices higher, citing higher ''replacement costs.'' Strangely, ''replacement costs'' never seem to work when oil prices are tumbling.