Readers of the recent series of articles on national defense ("Buildup: How Much for Defense?" front page, Nov. 28-Dec. 2) might be tempted to reach three conclusions: first, that widespread public support for defense spending had disappeared with the November elections; second, that current programs followed no particular strategy or the wrong strategy -- especially the Navy; third, that the nation could not afford to bear the cost of the resulting folly. These conclusions would be both false and dangerous.

The first argument about the consensus behind increased defense spending need not detain us for very long. Despite assertions by former officials about the significance of the recent elections and even the MX vote, I prefer the opinion of a man who knows, the Democratic whip of the House, Thomas Foley. He said: "There's a strong consensus to increase the military budget. We shouldn't take the MX vote as an indication that Congress is marching away from defense." The Post itself published a poll on Dec. 2 showing 54 percent of the American people in favor of maintaining current defense spending or actually increasing it (17 percent); only 24 percent favored a reduction.

What about the so-called defense experts, those former secretaries of defense and other officials whose views shape public attitudes? The nation surely owes these men a vote of thanks for their patriotic service; but just as surely, we owe it to ourselves not to accept assertions in place of reason. Nor should we allow a rich jargon to disguise an impoverished thought.

In contrast, the president's proposals are guided by a clear understanding that unless America upholds the balance of power, our diplomacy, our security and the security of our allies will be put in jeopardy. The Reagan "strategy" is to recognize that there is a connection between America's military might and international stability. The Reagan program is to invest now to make certain that we do not face in the future the deficiencies we have faced in the past--deficiencies that disturb us in the present. This is especially important in the case of the Navy.

Navies are very expensive even in peacetime because of their high rate of operation in a dangerous world. Moreover, a capital ship takes up to seven years to build. So there is a premium on the efficient use of current resources and farsighted planning for the resources of the future. "Current resources" and "farsighted planning" are indeed the key phrases that explain the Navy's current activity.

Our shipbuilding program to attain 15 battle groups and 600 ships by 1990 did not spring from thin air or the dreams of a would-be Napoleon of the Navy. Today's Navy must sustain permanent commitments greater than those of 10 years ago--in three oceans. And the Soviet threat is far more formidable in 1982 than it was 15 years ago when the U.S. Navy numbered 1,000 ships and 22 carriers. How odd then to treat the 600 number--a minimum figure-- as some inexplicable excess.

What are we going to do with this mighty fleet if deterrence should fail and war breaks out? Contrary to some assertions, we do not plan to launch the naval equivalent of the charge of the Light Brigade, with the Barents Sea the plain of Balaclava. But there is a good deal of difference between the foolhardy dispatch of our carriers against the Soviet cannon and the sitting-duck warfare disguised under the misleading title of "sea control." Sea control in this day and age is not to be won by waiting for the Soviet Navy to engage our convoys in the North Atlantic--a war of attrition that might be fatal to the defense of Europe.

The key to understanding our naval program is to see its relationship to other forces as well. The achievement of maritime supremacy, the goal of the 600-ship fleet, is a necessity if we are to sustain the coalition of free nations around the world that has deterred war with the U.S.S.R. for more than three decades. So the Navy is working to do its part in a team effort of forward-based air, land and naval power. Navy strategy is part and parcel of the national strategy of deterrence, not a substitute for it.

Finally, the issue of cost. Can the nation afford the president's defense programs? Can we do with less? "Cost" can be an elusive concept, as we in the Pentagon know only too well. But cost can be measured in several ways. An accepted method of estimating the defense burden is to measure it as a percentage of GNP, a figure that does heavy damage to the case of the critics. In 1982, the Reagan defense budget will take about 6 percent of GNP. Twenty years ago, the Kennedy administration spent 9 percent of GNP. Nearly 10 years ago, Secretary of Defense Melvin Laird recommended that 7 percent of the GNP be allocated. The defense burden on the national economy during President Reagan's tenure will certainly not exceed the historic norm -- unless, of course, we count the Carter years as normal.

Moreover, there is some good news for a change in the efficiency of our effort. In defense spending, as in any private business, a planned and consistent allocation of resources pays big dividends. In the Navy, as recent ship and aircraft contract deliveries attest, the cost of acquisition is actually coming down, and there is not one outstanding claim against the Navy for the first time in decades. The cost of ownership is also coming down dramatically. An Aegis cruiser is manned by only 25 percent of the requirements to man a Salem cruiser of 20 years ago. These achievements, combined with a drastic reduction of the inflation rate, provide solid evidence that there will be fewer --though less entertaining--horror stories from the Pentagon.

Solid public support for a stronger defense; a systematic strategy to repair our current deficiencies and to prepare for the future; and a defense burden easily within our economic capabilities -- these are the facts about the president's defense requests. The folly lies not in these facts but in the convenient beliefs, surfacing once again, that a job once started need not be concluded, and that the signal of a serious program is a substitute for carrying it out. Over the past decade, such tendencies have merely diminished national security and international stability. Surely the cause of freedom deserves a better effort.