CONGRESS SHOULD HAVE decided the Alaskan land question a long time ago. True, the choices are hard. Conservationists, as well as Alaskans, regard them as the most important environmental issues faced by Congress in decades. But by just letting the thing drag on, the Senate is making the eventual resolution harder still.

The House has twice passed an Alaskan land bill, in 1978 and again last year. The Senate Energy Committee reported its own version last November, but Majority Leader Byrd has been reluctant to schedule it for floor action. The inevitability of a long floor fight, the possibility of a filibuster and the conflicting positions of the two senators from Alaska -- not to mention the fact that this is an election year -- have all contributed to the delay.

But this is not the first delay. In 1971, Congress gave itself seven years to settle the Alaskan matter. You'd have thought that would be enough. But no. Then, when the legislators missed their own deadline 14 months ago, President Carter set aside 56 million acres of Alaska as national monuments. Now, Interior Secretary Andrus has said he will set aside another 50 million or so as wildlife refuges unless the Senate has decided by March 1 when it is going to take up the bill.

While Secretary Andrus is right to take this stand (an executive resolution of the problem is better than none at all), it is a bad way for such an important question to be settled. While this action by the secretary could be overridden by Congress (or set aside by future legislation), there is little reason to believe the Senate would be better able to get its act together after such a move than before it.

President Carter's action in late 1978 seems to have hardened the positions on both sides concerning almost every aspect of the issue. Those who want Alaskans to have greater access to federal lands than that Mr. Carter's action permits have heated up their arguments against the "great federal land-grab." Those who want strict federal controls see little reason to give up what they won with the president's decision.

The basic questions the Senate needs to face are how much of Alaska's wilderness should remain in the hands of the federal government, what degree of protection against development that land should be given, and where oil and gas exploration should be permitted.

The Senate Energy Committee's bill tilts far more toward the state government's position (low protection, more exploration and development) than either the House-passed bill or a substitute that will be offered on the Senate floor. That ensures a long, hard battle over spots such as the Artic Wildlife Refuge, Admiralty Island and Misty Fjords. It should get started before the Senate gets even more engrossed than it already is in the politics of a presidential election.