Cyrus Vance was the member of the Carter administration most widely respected abroad. To that extent, his resignation is bound, in the short term, to deal a blow to United States prestige and credibility.
But in the long run, the Secretary of State's break with President Carter may combine with the many other immediate woes besetting US foreign policy to expedite, even force, reassessments that some believe are overdue.
Few would question Mr. Vance's integrity and principled behavior. He has resigned on a point of principle: disagreement with the President over the wisdom of the hostage rescue attempt in Iran, which failed. Yet when the dust settles, there may be those who argue that Mr. Vance must share some responsibility for the setbacks to US foreign policy during the Carter presidency.
Admittedly, that foreign policy has had its successes: normalization of relations with China, the Panama Canal Treaty, and -- unless derailed in the months ahead -- the Egypt-Israel peace treaty. But on the main issue, the relentless superpower struggle with the Soviet Union, many foreign-policy specialists have charged that the Carter approach has been for too long naive and trusting.
Mr. Vance, partly because of his inherent decency, is regarded as having encouraged Mr. Carter in that approach -- even if Mr. Carter, because of his own decency, may have needed little encouragement.
The stark and unchanged fact is that the main threat to the security of the United States and its European and Asian allies comes from the Soviet Union. The Soviet leadership has never ceased throughout the period of so-called detente to seize every opening to manuever the US into a position of military and political inferiority.
A goodly section of US and European public opinion has been reluctant for over a decade and a half to face up to this; and political leadership in both the US and Europe has tended to reflect such an attitude.