Will Honor SALT Pact, Reagan Says : Agrees to Scrap Nuclear Submarine but Warns Soviets to End Violations

President Reagan, declaring he will “go the extra mile” in seeking to restrain the arms race, said Monday that the United States will adhere to the provisions of the second strategic arms limitation agreement, despite alleged violations by the Soviet Union.

Reagan announced that, to stay within the treaty’s limits, the United States will “deactivate and dismantle” an aging Poseidon nuclear submarine when the next Trident submarine begins sea trials in a few months--a deadline that forces a decision on whether to comply strictly with the treaty or ignore it.

Thus, after some of his most senior advisers clashed on what the Administration’s course should be, the President chose an option that makes no change in U.S. policy while awaiting moves by the Soviet Union. But, holding out the possibility of sterner action in the future, he said the Kremlin should be aware “that violations of arms control obligations entail real costs.”

No Plans for ‘Responses’

Reagan, who once called the 1979 SALT II agreement “fatally flawed,” declared that the United States will take “appropriate and proportionate responses to Soviet non-compliance” with the treaty, which was never ratified by the Senate. For the present, however, the Administration announced no plans for such action.

Reagan caught national security officials by surprise because it had been widely expected that he would place the Poseidon sub in drydock without taking the more stringent step of dismantling it.

He dispatched a letter to Soviet leader Mikhail S. Gorbachev on his decision, but there was no immediate reaction from the Soviet Union.

In Congress, the President’s decision generally won support, although some conservative Republicans criticized his refusal to build up the nation’s nuclear weaponry beyond the numbers allowed by the agreement, which would have expired at the end of the year.

An aide to Sen. Jesse Helms (R-N.C.) said Helms is “deeply concerned” and declared, “The forces which wish to perpetuate the mythology . . . of detente seem to have gained the upper hand.” Sen. Steven D. Symms (R-Ida.) said, “The Soviets are popping the vodka bottles tonight and saying they didn’t think the United States was that stupid.”

Meanwhile, Sen. Edward M. Kennedy (D-Mass.) said Reagan “wisely rejected the dangerous counsel of right-wing opponents of arms control,” and Senate Majority Leader Bob Dole (R-Kan.) asserted that Reagan “has set up a good test of Moscow’s true intentions.”

But Reagan’s decision, which closely followed the advice of Secretary of State George P. Shultz, left Defense Secretary Caspar W. Weinberger in the awkward position of overseeing the Pentagon’s compliance with the arms accord--upholding a decision he had vigorously opposed.

Weinberger issued a terse statement, saying only: “We are in full support of the President’s decision and have begun work on the assignment given to us.” However, one Administration official said that the Pentagon chief “didn’t want this treaty and doesn’t want to abide by it. He was clearly overridden.”

Under the treaty, agreed upon by President Jimmy Carter and the late Soviet President Leonid I. Brezhnev, each nation is limited to 1,200 launchers capable of firing long-range missiles carrying multiple nuclear warheads.

But when the submarine Alaska, the seventh Trident submarine to join the U.S. fleet, goes to sea for the first time in late summer or early autumn carrying 24 launchers, the United States will surpass that limit by 14. However, Poseidon submarines carry 16 launchers, so by dismantling one of those subs, the United States will stay within the treaty’s limit.

No Requirement to Destroy Sub

The agreement requires that the submarine’s launching tubes be dismantled, although the boat itself would not have to be destroyed and could be converted for training missions or to carry cruise missiles. The Soviets have followed the latter course with some of their submarines, according to Robert C. McFarlane, Reagan’s assistant for national security affairs.

Weinberger, like other critics of the treaty, has argued that the pact has had little, if any, effect in controlling the growth of Soviet strategic weapons. However, supporters of SALT II have maintained that the Soviets have retired missiles and remained within the numerical limits imposed by the agreement.

In a written statement that McFarlane read to reporters at the White House, the President said that “despite the Soviet record over the last years, it remains in our interest to establish an interim framework of truly mutual restraint on strategic offensive arms” while attempting to achieve “real reductions” in the superpowers’ nuclear arsenals.

“In the interest of ensuring that every opportunity to establish the secure, stable future we seek is fully explored, I am prepared to go the extra mile . . . ,” Reagan said.

Nonetheless, he said, the United States will continue to pursue the development of a small, single-warhead strategic missile dubbed the Midgetman. Deployment of the weapon is not expected until 1992 at the earliest.

‘Later Milestones’

In addition, Reagan held out the possibility that when “later milestones” are reached as additional Trident submarines are ready for deployment, he will assess Soviet behavior to determine what course the United States will follow.

In the Administration’s view, the Soviets have violated the SALT II limits, which allow only one new intercontinental ballistic missile, by testing two new such missiles: the SS-24 and SS-25. Moscow has argued that the SS-25 is a new version of an existing missile, the SS-13.

In addition, the Administration has claimed that the Soviets ignored the treaty’s prohibition on encoding data during missile tests.

“The United States has fully kept its part of the bargain. However, the Soviets have not,” Reagan said.

Asked why the President has decided not to ignore the treaty, McFarlane said that while the document was “fundamentally flawed in some respects . . . it can provide a framework for restraint if it is observed.”