As Congress moves to raise U.S. defense spending well beyond administration requests, Rep. Les Aspin (D-Wis.) has fired a salvo of statistics at his fellow lawmakers in an effort to rebut charges that the United States has been standing still in the nuclear arms race while the Soviets have been forging ahead.

Aspin's assessment appears today in the latest issue of the Bulletin of the Atomic Scientists.

Essentially, his analysis amounts to a reminder that the United States -- through a series of technical improvements to existing missiles, bombers and submarines in the last decade -- has not only kept pace with the effectiveness of Soviet weapons but has managed this at considerably less cost than Moscow, which has tended to build completely new weapons.

Though he doesn't address some Soviet trends that trouble those who favor a faster U.S. defense buildup, Aspin argues that the United States has been doing "as much as the Soviets have and far more cheaply and that, contrary to many doomsayers, we are not engaging in unilateral restraint or unilateral disarmament."

He urges lawmakers and the public to look beyond simple comparisons of numbers of missiles or submarines before making U.S.-Soviet balance of power judgements in the field of strategic atomic weaponry.

For example, the Soviet nuclear arsenal in the last decade has grown to a point where Moscow now has 2,504 ocean-spanning missiles and bombers compared to the United States' 2,058. This country however, through technology, has outpaced the Soviets in terms of how many individual atomic warheads those missiles and bombers can carry -- 9,200 for the United States, about 6,000 for Moscow.

That argument is well known. However Aspin also points out that less widely known improvements to the main U.S. Minuteman ICBM force have greatly increased its accuracy and the explosive power of its atomic warheads.

Both of those factors are of crucial importance in the arcane arithmetic of the arms race in terms of the ability of one side to knock out the other side's missiles in underground silos in a surprise attack.

Aspin claims that for an investment of about $880 million by the United States in recent years to improve Minuteman guidance and to add the more powerful Mk 12A multiple-warhead bombs carried by the missile, the United States has tripled the missile's effectiveness and kept pace with Moscow's silo-busting capability, which cost the Kremlin several billion dollars in new missiles.

Aspin argues that our improvements have been about six times more cost effective than Moscow's. But critics argue that Moscow's bigger missiles eventually will allow it to surpass the United States in number of warheads and targets that can be successfully attacked, including the 1,000-missile minuteman force.

Aspin also praises President Carter's decision to kill the proposed B1 bomber, saying that controversial decision, on purely technical grounds, "looks even better today than it did two years ago" when the president made it.

Aspin points out that the Soviets recently developed the new SAX10 anti-aircraft missile system, undoubtedly meant to defend against the B1.

The president's decision to go ahead instead with a new air-launched cruise missile to be carried by B52s, but which can be fired at long ranges outside Soviet air defenses makes much more sense, Aspin says.

Aspin also reminds readers that the B52s, though old themselves, have been improved with better electronic navigation equipment and armed since 1972 with nuclear-tipped short-range attack missiles, or SRAMs, meant to help the planes blast their way through to those targets they can reach with bombs.

The congressman also confronts those who worry that the nation's submarine-based missile force will face a dangerous period later this decade when the older Poseidon missile subs are taken out of service but not replaced by equal numbers of the newer Trident submarines.