Ever since the Saturday Evening Post merged with Respectability, the association has proved mutually profitable. Looking at the naughty but innocent urchins on its cover, the thrilling but insipid fiction in its pages, the homey cartoons, the clever "Perfect Squelch," and the biting but conservative editorials, one wonders whether America was conceived in the Post's image, or vice versa.

But in these days of feature-oriented newspapers and vitamin-supplement television, the magazine industry is deathly sick. Only T.V. Guide and Playboy are thriving; Coronet has just gone the way of Collier's,and the Post is en route to financial ruin.

Despite its confidence in a growing America, the Post finally undertook an extensive and expensive survey of its readership. The motivational researchers concluded that the magazine had about four years to live, unless it could greatly increase its appeal to young people. The Post was urged to change its image by emphasizing dissent.

Business after all, is business, and so last month the Post unveiled its new feature column "Speaking Out: The Voice of Dissent." Herman Kahn, publicity man for Civil Defense, helped christen the column by agreeing with 99 per cent of America on how necessary it is to prepare for war. The cynical quickly complained the new Dissent was only false advertising; but as one shrewd observer commented, "What Kahn actually challenges is the prevalent notion that nuclear war will somehow be unpleasant."

Both Esquire and Playboy have successfully modified their image by genuinely readjusting their contents. If the Saturday Evening Post intends to offer an effective forum for divergent opinion (and word of a forthcoming piece challenging the blacklist is heartening), a far more exciting and appealing magazine is in the offing. But Mediocrity by any other name will remain Mediocre