In the crisis precipitated by Premier Khrushchev's reckless adventure in Cuba, a head-on collision has thus far been avoided by virtue of the fact that since imposition of the blockade both sides have been moving with caution. This is all to the good. But the problems that have been raised are as far as ever from being solved.

  Acting United Nations Secretary General Thant's effort to ameliorate the crisis is welcome as a first initiative toward a peaceful settlement, and his appeal for talks is, of course, acceptable. But Mr. Thant's proposal for calling off the blockade and halting arms shipments to Cuba suffers from the defect that it fails to provide a remedy for the missile bases already there or even for safeguards against renewed deception by the Soviet Union.

  Premier Khrushchev finds it easy to embrace Mr. Thant's idea of a moratorium. To do so would permit him to continue shipping the interdicted arms to Cuba surreptitiously, as in the past, and to complete his nuclear build-up in Cuba. Under present conditions it would be folly for the United States to end the partial blockade. As President Kennedy emphasized in his reply, "the answer lies in the removal of offensive weapons from Cuba." They must be removed under guarantees which, as pointed out by Prime Minister Macmillan, will include adequate verification. But, in true Soviet Style, Premier Castro has already announced that anybody trying to inspect in Cuba must come prepared for combat.

  Nevertheless, sooner or later, negotiations must get under way, not merely on Cuba but on the whole world crisis. Premier Khrushchev has made clear his desire for a summit meeting and President Kennedy yesterday told Mr. Thant he was entirely agreeable to preliminary talks. The present contest over Cuba may well provide a start toward the conference table.