I Share Fred Charles Ikle's concern about "The Growing Risk of War by Accident" [op-ed, June 24.] His focus on the prevention of accidental nuclear war was laudable; his discussion was not.

Ikle says we have hobbled our strategic forces through self-restraint. This is not credible, when for much of the 1970s we added nearly three nuclear warheads a day to our arsenal, when we are proceeding to add now a new mobile ICBM, thousands of cruise missiles (permitted by SALT II) and new longer-range submarine missiles. Soviets forces have grown markedly during the last 10 years, but without the restraints of SALT I they would have grown far more.

For example, Ikle knows that our intelligence predicted a force of well over 400 Soviet heavy ICBMs, rather than the 300 SALT has held it to. And Ikle knows, too, that without the restraints of SALT II many hundreds more Soviet MIRVed missile launchers and up to 20,000 more Soviet nuclear warheads could be targeted on out nation. As a military man -- and as an American who wants never to see nuclear weapons fall upon our soil, accidentally or otherwise -- I am alarmed by the prospect ahead if we reject SALT II.

Ikle contends that our nuclear deterrent will become increasingly vulnerable. The reality is that fixed -- land-based missiles -- carrying less than 30 percent of our deterrent power but nearly 80 percent of the Soviets' -- are becoming more vulnerable as technology makes possible more warheads per missile and increased accuracy. SALT I did fail to stop this vulnerability; but for this, Ikle -- for four years a member of the team that negotiated at least 80 percent of Salt II -- must accept some of the responsibility.

I am disturbed that Ikle confuses vulnerability of a fraction of force with vulnerability of the entire force. First, he is wrong -- when we have thousands of invulnerable warheads on submarines and alert bombers -- and, second, such arguments could send a false message of weakness to the Soviets and bring on the very war we all seek to avoid.

Ikle criticizes SALT II for restricting mobile missiles. The only practical restriction on mobility -- in view of our program schedules -- is that mobile missile launchers must be coutable, verifiable. Since Ikle has often stressed the importance of verification, I am surprised that he downplays it on this occasion, for one sure way to increse nuclear instability is to permit the Soviets to hide hundreds, perhaps thousands, of nuclear missile launchers.

Ikle implies that "launch-on-warning" is becoming a cornerstone of our security policy. If this were trues, I, too, would be alarmed. However, Secretary of Defense Harold Brown, in his report to Congress, did not "raise the curtain" on a new policy. He merely restated what Ikle's colleague, then secretary of defense James Schlesinger, enunciated in his report to Congress for 1976. And I believe it's prudent policy -- no Soviet leader should never be allowed to think that we will stand idly by and wait out a Soviet first strike.

We do not rely on a policy of launch-on-warning to deter a Soviet nuclear attack, and we never have. At the same time, we have never precluded the possibility of launch-on-warning, since to do so would undermine the deterrent value of our forces. I must ask Ikle if he would wish the Soviets to believe that we would not launch any of our missiles until after the United States had been hit by Soviet warheads. Such a belief would give false comfort and confidence to the masters of the kremlin. And the result could be a fatal miscalculation.

Finally, despite Ikle's contention, President Carter has significantly increased the size of our defense budget. There is room for debate about how large the increase should be, but the increase is there, and it is substantial.

If we are to meet the Soviet challenge, if we are to reduce the threat of accidental war through miscalculation of our will and capabilities, then the foundation of our strength must be a steady consensus for a strong national defense. We have -- at last -- begun to reestablish this necessary consensus. Propagating myths and partisan rhetoric will surely blow it apart. The task before us is serious. It should be treated seriously.