Forget the history and the current polemics. Just as an intellectual exercise, look at what each candidate now says he would spend money on for defense. There are real differences between the candidates on strategic nuclear questions -- on arms control and on the pace of some cruise missile programs, for example. But when either gets down to putting programs together, a number of these differences may be narrower than they now appear.

For example, if he is elected, Reagan too may find it prudent to wait on the new Stealth technology before committing himself to a new bomber. And although several of his advisers are, understandably, eager to protect our Minutemen ICBMs in the early 1980s, he may find that "quick fixes" to do that will not exactly step along smoothly. For example, digging extra silos in order to move Minutemen around in a shell game to confuse Soviet targeting may be strategically desirable. But if he tries it he will be lucky if he gets his position for the legislative oversight hearings on the Arms Control Impact Statement coordinated with the litigation over the Environmental Impact Statement in time to get an analysis of both before the Defense Systems Acquisition Review Council when it considers the Mission Element Need Statement before the whole thing is canceled in the Office of Management and Budget's Spring Review of the Program Objective Memorandum for Fiscal Year 1986. And by then he can have MX.

So it is at least interesting to see if there would be major differences between the candidates in conventional -- i.e., non-nuclear -- military programs. Deng Xiaoping says that, when World War III comes in the 1980s, this is the way we'll probably be fighting anyway.

In two areas relating to conventional military capabilities, Reagan and Carter would probably have fewer major differences . If you look at what has been included in his proposed budgets, Carter has been pushing hard, and presumably Reagan would too, in the fields of immediate readiness and basic research. Readiness is far from what it should be, but lay that blame where most of it belongs -- with congressional cuts. Research cannot be managed more ingeniously than by Harold Brown and Undersecretary of Defense William Perry. There is no one better than these two at taking some exciting and far-out idea and pushing it toward military application. Stealth aircraft are just one example.

Reagan would clearly devote a larger amount to defense over the next four years. It's hard to say just how much, given his large tax cuts, but estimating from recent statements of both, $50 billion to $100 billion is not a bad guess. fBy the end of four years, then, Reagan would be spending a bit over 6 percent of the GNP on defense and Carter might be spending something over 5 1/2 percent. This is within a range of only two-thirds to three-quarters of the peacetime commitment to defense obtained by John F. Kennedy -- 8 1/2 percent of the GNP -- before our appetite for domestic programs grew so much in the late 1960s and 1970s. The difference between Reagan and Carter on defense spending is significant, but if you believe the numbers they are now giving, it is hardly overwhelming when put in historical perspective. (It's hard to say where candidate John B. Anderson comes out in all this. He proposes significant military pay increases, but on all other major defense issues he appears to agree with Carter or to be to his left: he has lots of time for sergeants but not much for their guns).

What could Reagan's larger budgets buy over the next four years? Mainly two things: improved quality of manpower, expecially in the now-hemorrhaging ranks of technically skilled noncoms and officers, and increased procurement of existing types of weapons -- today's tanks, artillery, ships, fighters, ammunition, etc. -- that the Soviets are now producing two to three times faster than we are. So you want to spend $50 billion or so on that over four years? That depends, primarily, on your judgment about the risks of conventional war in the 1980s and the utility of conventional military power in foreign affairs or in a crisis.

To the extent that you discount either or both of those, and think that we will get through the decade wtihout needing those trained men and added numbers of today's weapons, you can reasonably spend that money on other things. To the extent you agree with Deng Xiaoping, you would want to stock up.

By the end of the decade, the revolutionary efforts that Brown and Perry have pushed -- if continued and managed wisely -- may change the face of conventional warfare. Tanks bought today, for example, amy be vulnerable by then to extremely accurate sub-munitions dispensed by long-range missiles -- sending tanks where the English longbow sent French armored knights and where machine-gun fire sent the cavalry.

But it may take longer than a decade -- these things often do. You may have to fight, or at least convince the Soviets that you are able to fight, in the meantime. And it is going to be increasingly harder to do this in the 1980s with the type of military manpower and the low level of production of current weapons and ammunition we see today.