A master question confronts the Reagan administration. How can it cope with genuinely difficult national problems by diminishing the power of government?

Engery provides a crucial case in point. Even as the possibiity of a new oil shortage and another inflationary burst takes shape, the mechanism for making national energy policy is disintegrating.

The Department of Energy no bears responsibility for developing national policy. Ronald Reagan said, both as a candidate and as president, that he favors scrapping the department. He has named a secretary of energy who practically guarantees self-destruction of the department.

James Edwards, the new secretary, is a former Republican governor of South Carolina. He is said to have a quick intelligence and a sure political instinct. But for most of his life he has practiced dentistry, and he has absolutely no experience in the energy field. Many Democratic senators who voted for his confirmation expressed astonishment at his lack of qualifications.

William Proxmire of Wisconsin asked: "Is there any qualification with respect to energy that Mr. Edwards brings to this job?" Bennett Johnston of Louisiana remarked: "It seems to me that to have an appointment as secretary of energy who comes in without a strong background in energy is asking for trouble."

Trouble has already come in several forms. Edwards has experienced great difficulty in staffing the department and has repeatedly been turned down by highly qualified persons. He looked bad in briefing the press on oil decontrol and admitted he was "the new boy on the block." More important still, everybody in town is reaching for pieces of the energy domain.

Budget Director David Stockman, as usual, made the first grab. He, not Edwards, announced the decision to decontrol oil. He has prepared for the department a budget that slashes several programs, including one for producing oil and gas from coal that his country finances with its allies.

Interior Secretary James Watt, a skilled Washington hand who knows what he wants, has moved to raid DOE for top personnel. He is staking a claim to the management of coal and oil production.

The State Department is trying to take over international energy policy. Secretary Alexander Haig has talked about adding an assistant secretary for energy. One person State is considering is the prominent economist and former head of the RAND Corporation, Henry Rowen.

Right-wing ideologues shrug their shoulders at these developments. As they see it, the only energy problem was getting the government out of the business. Oil deregulation, they figures, should foster a new burst of production and the end of shortages.

Only all the evidence points the other way. Despite a huge price rise since 1973 and a record number of drilling rigs at work, there have been no major oil discoveries either here or abroad during the last decade. Most forecasters, including Exxon, predict a steep decline in American output. No one predicts an early end to dependence on oil imports.

Maybe continued dependence won't immediately flare into an acute problem. Stocks now held by consuming governments are very high. The recession in Europe, and the slowing of growth here, will cut demand. So the world could scrape by this year.

But the Iran-Iraq war is reducting production by about 5 percent daily. At some point soon, governments and companies will want to replenish the stocks they are now drawing down. When that happens, they will scramble to the spot market -- forcing up prices and touching off still another burst of inflation.

The prudent way to minimize panic is by an accord binding this country and its allies to draw down stocks and to go to the spot market only for the smallest supplements. But the only American instrument for managing such a policy is the Department of Energy. Domestic energy agencies have no standing abroad. And the State Department is always more interested in foreign policy objectives than in energy supply. As to the major companies, for all their virtues, Exxon and Mobil and the others are not primarily interested in holding down prices.

All by itself, in other words, the free market does not advance the national interest in the area of energy policy. While it may be desirable to give fuller play to market forces, at some point an opening has to be made for a mechanism that nudges the market in the direction of the public interest. But the Reagan administration is destroying that mechanism of cooperation in ways that alert other countries to go it alone. That erosion of the public authority in energy is the essence of the Reagan administration, and is taking place in many other affairs charged with the public interest.