In the shifting world of geopolitics and superpower relations, one question predominates: Which military alliance is stronger in Central Europe - NATO or the Warsaw Pact?
Two recent bits of significant but generally overlooked news illustrate the importance of this growing debate over balance of power. These are the latest United States intelligence estimates of Soviet military growth, and a new proposal by the Soviet Union to reduce both sides' conventional forces in Europe.
At mutual and balanced force reductions (MBFR) talks in Vienna, Warsaw Pact negotiators several days ago proposed new means to monitor and guarantee troop reductions. It was the first movement at these longstanding efforts in nearly a year. While NATO and US officials say important differences between the two sides remain, the new proposal is being closely studied by the West.
''It appears to be a move of interest and some substance,'' said one diplomat who has been close to the Vienna talks since their beginning 10 years ago.
At about the same time, the most recent information by the US Central Intelligence Agency (CIA) and Defense Intelligence Agency (DIA) on Soviet military spending was released here. This shows that the Soviet Union has been continuing its military buildup at a steady rate of 4 percent a year. Earlier this year, there seemed to be some difference of opinion between CIA and DIA analysts over whether the figure was this high. But this apparently has been resolved, at least among US government Moscow-watchers.
Such issues are crucial to efforts aimed at reducing the potential for conflict in Europe. But wide disparity of opinion remains over how assessments of military strength are made and how they should be used. Among the issues that are of increasing importance: quality of weapons and forces, size of arsenals (the so-called bean count), relative military spending, and strategies for using such forces or defending against their use.
''The US is producing the best equipment in the world,'' said Deputy Defense Secretary Paul Thayer this week. When asked by a congressional panel whether he would trade forces with the Soviet Union, the chairman of the US Joint Chiefs of Staff, Gen. John Vessey, emphatically replied, ''Not on your life.''
A recent report sponsored by the Center for Strategic and International Studies at Georgetown University noted that much Soviet weaponry ''tends to be inferior in quality and performance to the high-technology systems produced by the United States.''
There is more general agreement, however, that Eastern-bloc military equipment is catching up in sophistication. And there is little doubt that the Warsaw Pact generally fields many more tanks, artillery pieces, and other weaponry than the West. This point is emphasized by the Reagan administration and the Pentagon in seeking newer and more numerous weapons.
On the question of relative military spending, President Reagan often has noted that the Soviets outspent the US by $300 billion to $400 billion during the 1970s. But when allied contributions are added, the picture changes.
Tufts University Prof. Franklyn Holzman, who has done much research in this area, says the NATO-Warsaw Pact military spending balance for that period favors the West by $230 billion, or $480 billion if Soviet forces deployed against China are subtracted.
John Mearsheimer, a University of Chicago professor and author of the new book ''Conventional Deterrence,'' notes that the Soviet Union ''has terrible problems in being able to rely on (its) allies.'' At a seminar at the Roosevelt Center for American Policy Studies this week, he also said, ''We score much higher on operational readiness and training, which don't show up on the bean count.''
Other subjective judgments (such as the ratio of forces needed to successfully defend against a conventional attack) are part of the challenge faced by the West at the talks on conventional force levels. These talks have been going on in Vienna since 1973.
The major sticking points have been: how many troops the Warsaw Pact now has deployed; and how to verify any eventual reduction by both sides.
The general goal is to reduce both sides to about 700,000 ground troops. But until existing levels are settled, this is hard to do. NATO negotiators say the Warsaw Pact has 960,000 troops in the region, compared with the 800,000 claimed by Eastern-bloc representatives; pact officials say the West has more civilians in military jobs than does the East.
In its latest offer, the Warsaw Pact agrees to certain important verification measures, including monitors for troop withdrawals, permanent observation posts at entry and exit points, and possible on-site inspections.