PRESIDENT Johnson probably welcomed returning Korean envoy Cyrus Vance last week with a smile as big as a Texas barbecue. Vance, after all, had just pacified another of our finicky Asian allies--at what must have seemed bargain price: 100 million dollars in additional Korean aid. The calculable cost may indeed have been small. But on the balance, the Vance mission is a sad reminder of the short-sighted statesmanship which has generated America's open-ended Asian commitments.

The clash of interests in the mission was clear: the Americans were engaged in delicate negotiations to free the Pueblo's 82 crewmen, while Seoul, shaken by North Korea's escalating border raids was demanding pronouncements of American anger with the North Koreans. Vance avoided the verbal pyrotechnics which might have jeopardized the Pueblo talks, but at the same time the squawking South Koreans got essentially what they wanted. Vance's mere presence--and the 200 jet fighters the U.S. rushed to Korea--had the effect of renewing the blanket American commitment.

Blanket commitments, of course, are precisely what the U.S. cannot afford at the moment. Our pledge to defend Korea is not a new one, but age is not the test of necessity or desirability. The Koreans are far from defenseless. Their 600,000 man army--according to American propaganda, one of Asia's best--is nearly twice the size of their Northern enemy's. And though Korea depends on U.S. industry for weapons and some supplies, this hardly explains why two U.S. divisions patrol one third the length of the 38th parallel armistice line. The need for greater flexibility in our allied bonds is the clearest lesson of the Vietnamese mess. Vance's mission, however, ties an ostentatious knot in an unnecessarily tight U.S. commitment.

The patterns of events and emotions in this latest Asian crisis is monotonously familiar. There was first Korea's overreaction and talk of retaliation--unsupported by military power and strongly reminiscent of the belligerence of South Vietnam's rulers. Then came Korea's childish disregard for legitimate American interests--in this case, securing the release of the Pueblo's crew.

Finally, there was the enduring paradox of American relations in Asia: the ability of our allies to intimidate the American giant through protestations of weakness. The Vance mission clearly shows the Administration is slow to learn caution in handing out blank checks around the world.