ANOTHER year is coming. That means another defense budget and more talk about the arms race. Discussion has been started by a White House announcement that the President will ask for funds this coming year for making some of the new MX missiles mobile by putting them on railroad cars, and also for beginning work on a new, smaller mobile missile - the Midgetman. This is the obvious response to the fact that in 1986 the Soviets began deployment of a new, mobile intercontinental ballistic missile listed as the SS-25.
The US does not yet have any long-range ICBMs that are mobile on land. It has plenty that move around the oceans in Trident submarines, but the land-based US ones are all in big holes in the ground. They are too heavy, anyway, for mounting on wheels.
The Soviets have already deployed 72 of their new SS-25 missiles. Each has a single warhead rated at 550 kilotons of explosive power. More importantly, it is given an accuracy rating of 200 meters CEP. That means that, in theory, if 100 of these were to be fired at a single target, half would come within 200 meters of the target. Few targets could survive a 550 kiloton blast at 200 meters. No country has yet any long-range missile with a better rating than 200 meters.
The point about mobility is that you can't aim at the missile in advance. The US and the USSR know the location of all of each other's fixed long-range missiles. The US has a warhead aimed at every known Soviet missile, and vice versa. When you move a missile you deprive the other side of a known target and thereby reduce by one the other side's chance of knocking out your missiles before they can be fired.
Congress will undoubtedly provide funds for moving toward American ICBMs on wheels. This is the newest thing in strategic weaponry. We will have to keep up with the Joneses. But what about the overall arms race? Who is getting ahead?
In its latest annual report on the military balance, the International Institute for Strategic Studies (IISS) notes that ``the Reagan administration's defense buildup is over.'' By that they mean that the Congress in 1985 limited the amount of spending to what is presumed sufficient to finish projects in hand and keep existing armed forces more or less operational at present levels and with the weapons in hand or in building. There is not likely to be money out of the new Congress for expanding beyond present limits.
What are the Soviets doing? According to their own claims and reports (which Westerners do not accept at face value), they did not respond to the Reagan buildup until 1984. They then boosted their defense budget by 11.8 percent for 1985, but then leveled off for 1986 at the 1985 level.
Some of the increase has been turned into more ground power. They have apparently added one more motor rifle division and two air assault brigades to their order of battle. But mostly their new funds have gone into improving quality rather than quantity.
The IISS source cited above shows the Soviets with ``major developments in all major weapons categories.'' The deployment of the SS-25 is one of those major developments. Other developments include new and improved submarine-launched missiles, new and better submarines to carry them, and more planes equipped with air-launched cruise missiles. They have also deployed more of their new battle tanks and have shown some improvement in artillery.
Generally speaking, the numbers of Soviet units and weapons have remained constant, but with definite improvements in quality. The Soviets have not exceeded the SALT II limits in nuclear weapons. They have not materially altered the balance of conventional power in the European theater.
In other words, the race in 1986 was primarily in quality, and presumably will continue to be largely in that area in 1987. Neither of the two superpowers seems at the moment to be trying to gain a major lead over the other in quantity. There seems to be a tacit understanding that overall forces will be kept stabilized at present levels.