With prices at the gasoline pump falling sharply in many parts of the United States, and with continuing disarray among OPEC oil producers, it is imperative that the Reagan administration - and the American people - not again be lulled into apathy about the nation's future energy supplies. Indeed, the oil-producing nations could yet resolve their differences and come up with a unified price for oil. And as the events of the last decade have shown, an unforeseen political development in the Mideast - as when Iran slashed its production in the late 1970s - could again raise the possibility of dwindling oil stocks.
In this connection, it is encouraging that some lawmakers on both sides of the political aisle are concerned enough about the issue of future oil supplies and protecting conservation efforts to be considering a new tax on imported oil. Can such a tax be justified, given the need of consumers to have as much disposable income as possible to help spur the economic recovery? In part that question has already been answered by the Reagan administration, which has included a $5-a-barrel oil tax as part of its ''contingency'' tax plan that would go into effect in 1985 if federal deficits have not been brought down to acceptable levels by that time. Although the contingency tax proposal is not given much chance for enactment, the idea of the oil tax ought not to be dismissed out of hand by lawmakers. In fact, with prices falling, this is a propitious moment for imposing such a measure for it would not be greatly felt by consumers. The point is that a limited import tax, as favored by Republican Senator Domenici, head of the Senate Budget Committee, could help offset those bulging deficits and protect conservation gains already realized.
Naturally safeguards would have to be written into the legislation to terminate, or lower, such an import fee if oil prices were suddenly to cease dropping or, for whatever reasons, began inching upward again.
Meanwhile, there is one other aspect to the oil issue that deserves comment. It involves the Strategic Petroleum Reserve, which was set up back in 1975 to protect the nation against future oil shocks. After prodding by Congress, the Reagan administration moved with commendable dispatch to fill the reserve. By the end of this year close to half the storage in the reserves will have been filled.
But now, despite declining prices, the administration is seeking to slow construction of new storage space and substantially reduce purchases. Putting aside all the political factors involved - such as not wishing to offend Saudi Arabia, which has opposed the reserve - what happened to plain old-fashioned business sense? Obviously the time to buy is when prices are dropping and supply is ample. The administration ought to press ahead and fill the reserve as expeditiously as possible.
Americans who waited in long lines at the gas pumps back in the early 1970s and again at the end of that decade, should know better than to engage in wishful thinking about oil.