President Reagan once again has dramatized a televised speech with a call for no less than a changed national outlook on a long-standing national need. In his State of the Union address a year ago it was the concept of New Federalism to meet the need for governmental efficiency. In his national security address this week it was the concept of ''defensive'' technology in contrast with threats of massive retaliation to meet the need for deterring war.
Mr. Reagan's New Federalism was seen by many as a diversionary tactic in place of effective response to the economic problems that were mounting at the time. Yet it jarred some entrenched thinking on the subject. The ensuing debate has sharpened the views of Washington, governors, and the public as to the proper balance of state and federal functions and responsibilities.
Similarly, Wednesday's presidential call to go beyond prevailing military assumptions was immediately pegged by some skeptics as another ''New Federalism'' tactic to enliven one more warning about Soviet arms buildup. Mr. Reagan can disprove such doubts by a vigorous follow-through with specific proposals. These could spark debate helping the nation toward a valuable self-scrutiny on just what its long-term national security strategy should be. Such scrutiny is demanded not only by continuing Soviet nuclear buildup but by the whole range of new mega-weapons at hand or on the horizon.
In simplest terms, Mr. Reagan was asking American scientists to be as effective in developing systems to stop nuclear missiles as they were in developing nuclear arms in the first place. (These antimissile systems presumably could involve lasers, particle beam generators, and other space-age weaponry on which research is already well under way.) Thus the United States and its allies would be safe from an adversary's missiles without having to deter their use by the present threats of retaliation.
By raising the prospect of an alternative to deterrence-by-threat Mr. Reagan may have been speaking to a recently publicized issue: the questioning by religious and other disarmament advocates of the morality of a deterrence based on a doctrine of massive nuclear retaliation. Suppose the deterrent failed and an enemy attacked, they ask, would it then be moral to carry out the threatened retaliation at the cost of global or near-global nuclear destruction? In theory, the question would not have to come up if America could physically deter any weapons from coming in - and thus not be presented with the decision of whether to retaliate. Mr. Reagan cautioned that the day of such defensive security would be far in the future. What he would do as a matter of policy is to hasten that day.
The debate now will have to include the question of whether the development of ''defensive'' arms would simply lead to a new round in the arms race. Presumably Moscow, which is already said to be moving vigorously on space weaponry, would seek to match anything the US did. If Soviet antimissile defenses became impregnable, the missiles of America's European allies would lose whatever usefulness they now have.
No wonder arms controllers are looking beyond whatever happens in the current nuclear arms talks to the arms control of the future. Quality as well as quantity will have to be a subject of negotiation. Experts don't expect research and development to be brought to a halt. But deployment of their results might be controlled by ensuring that arms control negotiations keep pace with the new weaponry at every stage.
Yes, arms specialists have long been aware of what Mr. Reagan was talking about on Wednesday. But by introducing it to the American people as part of a ''vision'' for peace in the future, the President calls upon them to join in rethinking the concept of defense they want to have. Will the arsenal of the future be such as not to require a strategy of threats by people against people? To open that possibility is no small thing. It might even make people examine how the thought and conduct in their individual lives can contribute to national attitudes rendering war as well as weapons obsolete.