The best place of all around here to get on the trail of dinosaurs is an hour's drive out into the Virginia countryside south of Leesburg. There, in the flagstones surrounding a magnificent white-columned mansion, are the clear marks of footsteps, tail-draggins and lying-down hide marks left by Plateosaurus and Coelophysis two million centuries ago. An eerie experience -- for to stand there and look down at those clear prints, with their sharp, fresh claw marks, is to see one's own national history as not much more than a gnat sneeze, and to feel oneself keenly the contemporary of the man who built the mansion -- James Monroe, fifth president of the United States and the author of the "doctrine" that bears his name.

These dinosaur messages were quarried from the property some time after Monroe passed on, so he never knew of their existence, although one suspects that he would have understood the savagery of the primal swamp, where realism was all and sentiment could get you dead in a hurry. For Monroe, a realist himself, knew mortal strife firsthand and held himself aloof from those who would meet force with hysteria. Although, when you consider the bombastical ways in which his name is invoked, you would never know that.

Monroe, after all, was not trying to create Holy Writ when he set forth the doctrine, but was responding in a practical way to a specific threat: the possibility that Russia, in concert with her allies, might swoop down on Latin America and, by so doing, carry out in this hemisphere her oath to "put an end to representative government in whatever society it may exist." This was a real menace, and Monroe, in repsponding to it, was characteristically cool-headed and tough.

And thus, in the message he delivered to Congress on Dec. 2, 1823 -- and which, it sometimes seems, not many present-day orators take the trouble to read -- he was trying, not to dazzle his countrymen, but to inform them; not to stir up their aimless passions, but to enlist their rational support. Therefore, everything he had to say about Europe keeping its claws off the Americas was prefaced by strong arguments on a prior and controlling notion -- namely, that no effective defense was possible without public support and that no public support was possible without the government faithfully informing the citizens of the dangers confronting them and setting forth for their approval the policies that needed to be implemented by way of reply. This was vitally necessary, he said, because "we are all liable to error, and those who are engaged in the management of public affairs are more subject to excitement and to be led astray by their particular interests and passions than the great body of our constituents." Indeed, the real Monroe Doctrine has more to do with this principal than it does with the hands-off policy on Latin America.

He was cautious, leaving the possible consequences of stepping over the line he had drawn as only implied. For Monroe shared with William Wirt, his attorney general, an apprehension "upon the danger of assuming the attitude of menace, without meaning to strike." But he drew the line anyway, on the assumption that those who followed him into the presidency would likewise be realists, who, in the words of a latter-day television gunfighter, would draw only if they intended to shoot and shoot only if they intended to kill. And he was right about that, too, because the Monroe Doctrine has never been invoked beyond our power to back it up. In fact, when our power has been great, we have tended to use it in ruthlessly unscrupulous ways -- as in Teddy Roosevelt's era of the big stick. When we have been weak, on the other hand, we have backed off; and indeed, for half its life the Monroe Doctrine was enforced by the British navy.

That document, then is neither so venerable nor so absolute as recent orators have made it out to be. And so it comes as jarring that Dr. Henry Kissinger, in a recent speech before the American Bankers Association, felt called upon to use it as a kind of bugle to rally the troops; even going so far as to assert that the Soviet brigade currently in Cuba is "the first organized hostile force in this hemisphere since the Monroe Doctrine that we have accepted."

In the first place, of course, this isn't so -- that particular honor belonging not to any 3,000-man Soviet brigade, but to the 190,000-man Cuban army, which is as fully under Russian control as the Russian army itself. Moreover, the accepting was done way back in 1962 and has been maintained ever since, with no noticeable exception during Kissinger's own time in office.

In the second place -- and this goes for many of the Monroe Doctrine rodomontades these days -- the tone of those remarks was both rancorous and absurd; seeming to imply cowardice on the part of the president, or maybe on the part of the non-bankers generally; and seeming to suggest that if we would be true to the cool-headed rationalist who wrote the doctrine, we would be rash and self-destructive.

True, an escalating series of sanctions might, and maybe ought to be, applied. None of these, however, is likely to modify the Soviet Union's hostile adventurism in world affairs, even if the brigade in question does withdraw. For that we need not the trumpetry of ambiguous slogans, but the swift and rational expansion of our military capability -- about the same course Kissinger was advocating before the banker's speech, and one he would do well to stick to.

In the meantime, the larger issue, on which all our foreign policy depends, has to do with how American leaders ought to rally support for necessary policies -- whether by declamation or by reason. In that context, if we are going to bring up the Monroe Doctrine, we would do well to bring all of it up -- including the part where its author insists that effective action without public knowledge and support is impossible. For the Vietnam War should have proved, if nothing else did, that it is arrogant, destructive and ineffectual to keep the information and decision-making in the back room and then to go out fiercely onto the podium to try to rouse popular support with sentimental slogans from a past that never existed. In the slash and gnaw of geopolitics, sentiment cannot be expected to manufacture what self-interest is unwilling to supply. And to his great credit, Monroe knew this and would have understood those creatures whose tracks encircle his home -- which, having never been subject to a single rabble-rouser, nor even any gratuitous history lesson, managed to live around here for 130 million years by dealing realistically with situations as they arose.