The new stamp tax

Mail delivery in the United States would have to be considered first rate. Still, many Americans would rightly argue that the US Postal Service has far to go in making its service as productive as possible.

We mention this because of the strong possibility that postal costs will scoot up next year. The independent Postal Rate Commission has now given the go-ahead to a rate increase for 1985, as sought by the Postal Service. The proposal now goes to the Postal Service board of governors, which seems likely to approve the increase.

If approved, the package would mean a rate increase of $2.2 billion. Among specific changes: The cost of a first-class stamp would rise from 20 cents to 22 cents. A post card would go up a penny, from 13 to 14 cents.

The larger point is that the Postal Service - as required by law - continues to turn out surpluses. In fiscal 1982, the surplus was $802 million. In 1983, it was $616 million. A surplus is again expected this year. But the question is how it is doing that. One business leader who heads up a group of financial institutions that are large users of first-class mail contends that the surpluses ''are not due to good management.'' Rather, he argues, they are ''due to the fact that the Postal Service has been overcharging the public for three years.''

Congress might well take a close look at such allegations. Surely, the American public should feel justified in properly funding its Postal Service. But considering the tales of woe so often heard from citizens encountering their neighborhood post office - the inability just to catch the eye of a loitering clerk in a jammed line, for example - one cannot help but wonder if the service has yet gone as far as it could in adopting better management practices, including using computers and automatic data sorting systems. A final point: Each increase in postal costs may be self-defeating for the system, in the sense that businesses are then inclined to look to private mail services to handle delivery - but at a far lower cost. But each time that happens, guess who gets stuck with the added costs of paying for the Postal Service?