Bravely, Caspar Weinberger, secretary of defense, addresses the question of how some of his critics got the impression that the administration was pouring large new sums into defense without knowing what it was spending the money for. It was urgent, he said the other day, to start "rebuilding" immediately -- this by accelerating or augmenting existing programs. But "little was to be gained by an early enunciation of some elaborate 'conceptual structure,' a full-fledged Reagan strategy. Too often, in the past, these easy and early pronouncements have caused real harm. They prejudged and oversimplified reality; they put blinders on our vision."

So much for the splendors of unblindered policy-making. But now that, as arms control director Eugene Rostow put it, Congress has taken "its histroic votes on the future of the military budget" -- that is, the administration has the money -- Weinberger is enunciating a conceptual structure, one chosen, he reports, with "care and thought." Take a look.

He starts by defining "our most basic goad . . . to maintain peace with freedom. Peace alone is not enough. In a tortured sort of way, Poland is at peace. We must have freedom with peace." Pure Reagan, you might say. But is Weinberger really means to reach into the Warsaw Pact and gain freeddom for Poland, he is taking American defense policy leagues beyond the purposes -- to keep the East-West peace, to maintain the poise of our friends -- to which it has been devoted since World War II. Does he accept these provocative implications of his words?

Weinberger says we must improve not merely the strength but also the readiness of our forces, and their "substainability." By the latter he means that the old certainty that our neclear superiority precluded a "prolonged, major conventional war" has faded. We must also prepare to expand defense production "massively" in an all-out emergency. To all of which I say that, in general terms, this is what Ronald Reagan was elected to do.

But it is necessary to add that, in specific terms, only a brief review of policy has been conducted inside the administration and virtually none outside. pThe Pentagon's descretion and the discombobulating effects of this year's budget process ensured that.Was it smart to devote those immense 1981 and 1982 budget increments to expanding existing programs? What new programs might make sense in the out years? I note the absence in Weinberger's statement of any trace of interest in the intriguing military "reform" movement, an effort to move the defense debate beyond traditional budgetary questions into issues of the efficacy of military power.

It is a bit disappointing to find Weinberger still broadcasting an unnuanced version of the essential Reagan idea of America the pygmy power, hanging on to life and liberty by its fingernails. To concede that there are some strategic factors working for us, along with others working against us, apparently would spoil the effect he seeks. One looks in vain, for instance, for some awareness that Poland's revolution, regardless of how it ends, has both ripped and revealed a vast permanent hole in the Soviet Union's most important front.

The secretary anticipates "bolder Soviet military initiatives . . . the possibility of conflicts in widely searated areas: Central Europe, the Persian Gulf, Africa, East Asia or Central America. We may have to deal with more than one conflict at a time; and we must be able to contend with a conflict in on area without opening up critical vulnerabilities elsewhere . . . we will not restrict ourselves to meeting aggression on its own immediate front . . . we must be prepared to launch counteroffensives in other regions and try to exploit the aggressor's weaknesses wherever they exist."

Well, it is true that the Soviet Union, with its proxies, has been bolder in recent years. It is not possible to exclude that it may try to exploit the "window" of the next few years before the new budgets are converted into real military sinews. I do not dismiss the potential deterrent effect of pronouncements like Weinberger's.

But his thermostat is too high. His reading of international threats is too fevered. He speaks as though he still needed to demonstrate American will; actually, the quality in question is judgment. As great as are the new resources the administration intends to put into defense, not even these will equip it for all the large and simultaneous military operations it envisages. With all due respect to the reasons for playing one's cards close to one's vest, it does not appear to me that any hard choices have been made.

Worst of all, this administration seems virtually bereft of ideas on how to capitalize diplomatically on its distincitive assets: Reagan's credibility as a tough guy and the Pentagon's budgetary surge.