ON MARCH 9, the United States Senate, by a vote of 58 to 40, confirmed Paul C. Warnke as the nation's chief negotiator at the SALT talks and director of the Arms Control and Disarmament Agency. Warnke will bring to his new responsibilities a freshness of perspective on defense matters not seen in Washington for years, and if his cool performance before the antagonistic Senate Armed Services Committee is any indication, he will be an open-minded but tough negotiator when he and Cyrus Vance travel to Moscow later this year. Carter's appointment and the Senate's confirmation of Warnke are the first steps in what could be a successful effort to exercise a long-awaited restraint on the production of nuclear weapons.

But having weathered the considerable efforts to kill his nomination, Warnke and Carter will face new obstacles. Despite a personal plea from Carter linking the success of the Warnke nomination to respect for his ability as chief negotiator, the margin of confirmation in the Senate fell short of the two-thirds majority that administration officials desired both as a symbolic expression of support and as an indication that a possible arms control treaty with the Soviets would not be doomed from the start. Opposition to Warnke's nomination seemed to be based not on Warnke's lack of qualifications, but because he was too well qualified. The target of the attack was not so much Warnke but the prospect of mutual controls on the arms race.

Since President Carter has established the rational control of nuclear weapons and nuclear proliferation as his principal foreign policy goal, Warnke's opponents effectively were endeavoring to undermine and, if possible, destroy the president's principal international objective. The 40 votes against Warnke are evidence of the strength of this feeling in the Senate and a signal of more trouble to come.

It is apparent that too many of the nation's leaders have failed to recognize that the risks of nuclear war will not be abated by a continuing and sometimes witless expansion of the nuclear arsenal, or an attempt to torpedo arms control negotiations before they start. The risks of war can only be diminished by a mutual willingness on the part of the Soviet Union and the United States to make together concessions that will increase the security of each. The Soviets claim that they are willing and eager to conclude new SALT negotiations. The time has come for the United States to test their good faith.