When the conversation shifts from what a limited choice there is among presidential candidates, Walter Cronkite is one of the names that always turn up as for-instance alternatives. Eight years ago, he was one of ten possible vice-presidential running mates listed by Democrat George McGovern. Last week the New Republic quoted him as saying he would be honored if asked to accept a similar spot on Republican John Anderson's independent ticket. Obviously such a remark must have given CBS fits, putting in jeopardy in the midst of the campaign its star anchorman's reputation for neutrality. Cronkite, off on a...

