A chart on Page A30 yesterday incorrectly stated the growth in Soviet ICBM warheads, as reported by the Defense Department. The number of such warheads has increased from 5,302 in 1981 to 6,300 in 1984. The 1984 figure was incorrect.

During his 1980 campaign for president, Ronald Reagan declared: "We cannot negotiate arms control agreements that will slow down the Soviet military buildup as long as we let the Soviets move ahead of us in every category of armaments."

Candidate Reagan pledged to build U.S. military strength as the necessary foundation from which to negotiate fair reductions with the Soviet Union.

Today, asserting that the United States no longer is "inferior" in military power, Reagan has declared that he is prepared to negotiate from strength to achieve an arms control agreement, now designated as his top foreign policy priority.

The president no longer speaks of a U.S. "window of vulnerability" because of the overwhelming Soviet advantage in land-based intercontinental ballistic missile warheads. This year he even said he sleeps soundly in the White House despite the presence of new Soviet missile-launching submarines off the U.S. coast, "because I don't think they pose any particular threat at all."

In fact, the best available figures indicate that the relative nuclear arms strengths of the United States and the Soviet Union have changed little in the past four years. The Soviets have lengthened their already long lead in land-based intercontinental missiles, which Reagan previously marked as the most important category. The United States, at the same time, modestly improved its leading position in submarine-launched weapons and strategic bombers.

How then does Reagan's "strong" United States in 1984 differ from the "weak" United States of President Jimmy Carter in 1980? And what is the likely impact on the future U.S.-Soviet arms negotiations which Secretary of State George P. Shultz and Soviet Foreign Minister Andrei A. Gromyko hope to arrange when they meet in Geneva Jan. 7-8?

The nuclear arsenals underlying the "balance of terror" in the postwar world have become political weapons as much as, or more than, military weapons. Because their use would bring a holocaust for both sides, their purpose is to impress the foe more than to attack him.

The measurement of strategic power in these circumstances goes well beyond the sheer numbers, megatonnage and delivery systems listed by "nuclear accountants" and can encompass prestige, perceptions and essentially political judgments.

Thus it is possible with little change in the accumulations of arms for Reagan simply to assert that the United States has rebuilt its strength and for many people here and abroad to accept this without argument.

Sen. Steve Symms (R-Idaho), a leading critic of existing arms control agreements, said in an interview that the gap between U.S. and Soviet strength has closed because "just Ronald Reagan's election made us stronger . . . . It's a state of mind."

Former defense secretary Harold Brown said that the Reagan administration has spoken as if additional U.S. military capabilities have been deployed on its watch, but that "what has been been deployed was funded by prior administrations." In this sense, he said, Reagan's statements about the increased strength of U.S. strategic forces have been "self-serving and misleading."

In the four years of Reagan's presidency, according to Defense Department data, the Soviet Union has increased its lead in ICBM warheads by about 1,000. The U.S. reduction in its ICBM warheads came about because older Titan missiles were being retired and the new MX missile is only in its testing phase.

In submarine-launched ballistic missiles, the least vulnerable part of the force and the one where the United States has a big lead, U.S. warheads increased by 400 under Reagan while the Soviets increased by 644.

In strategic bombers the U.S. force declined by 45 under Reagan as old planes were retired, but they gained additional power because many were armed with air-launched cruise missiles. The Soviets in the same period increased their strategic bomber force by 60 Backfire bombers.

The United States and its allies made a large-scale effort to close the gap in the deployment of medium-range missiles in Western Europe to match the Soviet deployment of medium range SS20s aimed at the NATO countries. But here, too, the numbers show that the Soviets continue to dominate, since they added warheads at a faster rate than did the West.

The United States in the past year has deployed the first 109 Pershing II and ground-launched cruise missiles in Western Europe, each with a single atomic warhead. But the Soviet SS20s targeted against Western Europe have three warheads each, and they have increased from around 300 warheads in 1981 to 729 warheads today.

"The strategic balance has not substantially changed in the past four years," said Edward L. Warner, senior defense analyst of the Rand Corp. and a former assistant to the Air Force chief of staff. "There is still a rough parity between the two sets of forces, now a little bit rougher than before on the United States."

A recent report of the Committee on the Present Danger complained, "While real U.S. defense expenditures have increased marginally in the past four years, the gap between U.S. and Soviet military capabilities continues to grow."

This group, which spread the alarm about the Carter administration's "inferior" military position when waging the battle against the SALT II treaty, contributed 61 of its board members to administration positions, including Reagan and the man he recently named as senior arms adviser to the upcoming Geneva discussions, Paul H. Nitze.

[White House officials said yesterday that they expect only Nitze and perhaps a U.S. recorder to accompany Shultz into the talks with Gromyko at Geneva, with an array of other officials from the State and Defense departments, Arms Control and Disarmament Agency and Central Intelligence Agency waiting outside. This unusual procedure, if accepted by the Soviets and others in the U.S. government, would strengthen Nitze's role.]

Whatever the significance of the numbers, it is clear that both sides are continuing at great cost their race for more powerful and sophisticated weaponry.

The United States is testing or deploying a new strategic intercontinental missile, the MX, a new class of missile-launching submarines, the Trident, and a new heavy bomber, the B1. It is developing a small mobile missile, the Midgetman, a more powerful submarine-launched missile, Trident II, and another bomber, Stealth.

The Soviet Union has just completed improvements on three intercontinental missiles, the SS17, SS18 and SS19. It is deploying two new classes of missile-launching submarines, the Typhoon and Delta III, and a new bomber, the Backfire. Two more new missiles, the SS24 and SS25, are in final stages of testing and still another, the SS26, is under development. It also is developing a longer range submarine launched missile, SSNX23, and has begun flight testing another new bomber, the Blackjack.

The newest wrinkle, introduced by Reagan in March 1983, is the search for a far more effective defense against missiles, his Strategic Defense Initiative, popularly known as "Star Wars."

Both sides have been pursuing active defensive programs for decades, but the 1972 SALT I treaty limiting antiballistic missile systems (ABMs) brought a limit in the past decade to the intensity and extent of these efforts.

This new emphasis on defense, which holds out only a slim promise to produce weapons systems soon, is having a profound impact on discussions of the nuclear balance and particularly on how each nation approaches arms control talks.

Renewed bargaining on arms control, which Shultz and Gromyko hope to arrange next month, will have to take into account the current strategic balance and the military programs under way or on the drawing boards.

The total numbers, especially the continuing increase in the Soviet lead in ICBM warheads, suggest that it is even less likely that Moscow will agree to "deep reductions" that would bring its totals in line with the United States.

The Reagan administration's initial goal in strategic arms control was to persuade the Soviets to make big cuts in the area where the Soviets were far ahead.

One possible approach to improving the U.S. position without requiring such large-scale Soviet reductions is beginning to emerge in interagency meetings and the comments of key officials. Under this approach, the U.S. side would neutralize some of the Soviet advantage in land-based ICBMs by placing a limited number of ABMs around U.S. land-based missile sites. In this way the United States could protect its retaliatory force from attack even though the balance of offensive forces was still against it.

This probably would require a change in the ABM treaty, which permits one ABM system on each side. An ABM defense of some U.S. missile sites also would be a costly new military program at a time when the administration is seeking to make budgetary cuts.

Brown, the former defense secretary, said last week that a limited ABM defense of U.S. missile sites would cost more than $10 billion.

In recent months such officials as Assistant Secretary of State Richard R. Burt and Assistant Secretary of Defense Richard N. Perle, who often have been at odds over arms control policy, have spoken of the need to consider both offensive and defensive weapons in formulating a revised U.S. position in arms control negotiations.

Something of a consensus on reviving a tradeoff betweeen offensive and defensive weapons emerged within the administration last summer after the Soviets offered to discuss space weapons in Vienna in September. That approach had helped lead to the 1972 SALT I treaty to limit defensive antiballistic missile systems and a simultaneous interim agreement limiting offensive strategic nuclear weapons.

Although the Vienna talks fell through, Reagan said in his address to the United Nations General Assembly Sept. 24 that the United States is prepared to discuss "the relationship between defensive and offensive forces" with the Soviets in arms control negotiations. This formulation or some variation on it is likely to be put on the table by Shultz when he meets Gromyko next month.