The United States now spends more money buying weapons than does the Soviet Union, according to official Defense Department figures. The USSR was the world's premier arms spender through the 1970s and early '80s. But a little-noticed chart in the Pentagon's recent annual report to Congress reveals that the US took over this title in 1984.
Lush US defense budgets in the Reagan years are one reason for the switch. Another is that Soviet forces have fallen on relatively dry times.
``The growth of Soviet military procurement . . . appears to have leveled off after 1976,'' notes the Pentagon annual report.
The USSR's weapons budget was about $68 billion in 1976, and slowly rose to about $74 billion in '85, according to US figures. By contrast, US military procurement (including some non-Pentagon funded programs) went from about $32 billion to $77 billion in the same period.
Pentagon officials have long used such dollar comparisons as a way of making political points: in this case, that the Reagan buildup has strengthened the military. The administration has become sensitive to charges that its increased defense budgets have been funds ill-spent. In a speech to the nation scheduled for tonight, President Reagan will defend his military policy.
Experts caution, however, that the dollar comparisons with the Soviet Union are in fact very inexact, at best useful for indicating trends over a period of time.
The problem lies in figuring costs for the Su-27 Flanker jet, T-80 tank, and other new Soviet weapons from sketchy intelligence. Without detailed knowledge of a weapon's fine points, it is difficult to estimate what resources went into its construction.
When the CIA got its hands on a captured MIG-25 fighter in the late '70s, for instance, it discovered that the plane was a heavy fuel-guzzler that needed a more powerful, and much more expensive, engine than US analysts had thought.
In addition, the estimation requires establishing a dollar value for rubles -- a task at which economists throw up their hands. ``The methodology for the whole process is pretty awful,'' says Richard Stubbings, a Duke University administrator who was a White House defense analyst for 20 years.
Mr. Stubbings adds that even if the US annual weapons budget is richer, the USSR continues to produce larger numbers of key weapons, such as tanks.
In 1984, the Soviets produced 3,000 tanks; the US, 770, according to Library of Congress figures. USSR tactical aircraft production was 640 that year, to 250 for the United States.
One explanation for this apparent paradox is that Western weapons are more expensive, per unit, loaded with exotic radars, laser range finders, night-vision devices, and other accessories. NATO nations have long emphasized quality over quantity in their effort to equal Warsaw Pact conventional forces.
``We do buy the most complex weapon systems in the world,'' notes Richard Kaufman, Joint Economic Committee general counsel and an expert on the comparative value of US and Soviet forces.
The two superpowers also simply have different tastes in arms. The USSR emphasizes armor; the US buys lots of anti-armor weapons. The USSR has large land forces; the US has long lavished money on seapower. There are, for instance, no Soviet counterparts to the expensive American Nimitz-class aircraft carriers.
``A good deal of our procurement is concentrated in the Navy, where we don't lag behind the Soviets,'' says Abraham Becker, author of a recent Rand Corporation study on Soviet defense spending.
For US analysts, one of the most intriguing mysteries in this issue is why, in the face of the Reagan buildup, the Soviet Union has apparently slowed the rate of growth in its own military budget.
In congressional testimony several years ago, a high CIA official mentioned a number of possible reasons: industrial bottlenecks, technical difficulties, perhaps policy decisions. Mr. Becker says he believes Kremlin planners do not want to pile more military spending on the already-strained Soviet economy.
To the Pentagon, however, the Soviets are still ahead in an important value measure. This year's annual report claims that years of steady spending have given the USSR a total stock of military equipment worth some $300 billion more than US inventories.