The 1982 US congressional legislative session has been marked mainly by consideration of the federal budget and controversial ''social issues'' such as abortion and school prayer. Yet, hidden away in all the various Capitol Hill maneuverings has been a potentially crucial tug of war over what do with the nation's vast wilderness system. It is between the Reagan administration on one side and, on the other, Congress and the environmentalists. One particular aspect of that clash stands out. To put it in succinct terms, the administration is asking Congress - and the American people - to accept a ''limitation'' on the future expansion of the US wilderness system.
The administration proposal should be rejected out of hand. Accepting such a limitation through legislative action would be unwise and could open large amounts of potential wilderness areas to commercial development and mineral exploitation. Moreover, the move makes little sense since, presumably, imposing such legislative restrictions now would not bind future Congresses anyway.
The administration last week asked Congress to free up and release for potential development millions of acres of land administered under the US National Forest System. Under the proposal, the administration would accept a ban on mineral development in wilderness sites. The quid quo pro, however, would be the proposed limitation on future expansion of the system.
To break down the numbers:
* Some 15 million acres of forest land have been recommended as potential wilderness areas, subject to final approval by Congress. Some congressional action has already taken place.
But most of the land is in effect on a ''hold'' status - administered as wilderness areas but not yet officially approved as such.
The administration is urging that lawmakers impose a timetable by which Congress could decide whether the 15 million acres officially become wilderness, or not.
* Meantime, 36 million acres have been recommended for nonwilderness use. Environmentalists in California and elsewhere have challenged the process used to reach the nonwilderness status. Court actions are underway.
The administration is urging that lawmakers offically ratify the nonwilderness designation and thus free up the 36 million acres for multiple usage, including development.
The administration has a strong case in urging Congress to act with greater speed in deciding which lands it does favor for wilderness protection. On the other hand, lawmakers have had their hands full with budgetary considerations this past year. To pressure lawmakers to reach hard and fast decisions on wilderness questions serves little public good - and has the potential for much mis-chief.
The nation's wilderness system is one of its proudest treasures. Congress must continue to act with great prudence in matters involving that system. Lawmakers should resist any effort to limit its future growth or pass legislation that would bar court action affecting which lands are - or are not - designated as wilderness sites.