Two midsummer communications:

The ones that come in over the transom are always unsigned, as was one a few weeks ago on State Department stationery. It was addressed as a memorandum to Post publisher Donald Graham with a copy to me. It said: "The Post was and is an obvious and logical target for infiltration . . . . The only value of a Soviet agent in a newspaper is that he write or suppress a certain point of view. It should, therefore, be possible for editors to maintain some control . . . by spotting those who . . . support the Soviet line during key moments of decision on critical issues." This . . . after saying "we make some efforts (at State) to keep an eye on things." That is good to know.

The subject of this raving paper, officially repudiated by the State Department, is former Soviet KGB chief Yuri Andropov, who was elevated last May to Central Committee membership and is now in the line among those speculated to succeed President Leonid Brezhnev.

At that time, a Post story from Moscow attributed to "Western analysts" that Mr. Andropov was "a well educated and enlightened man--even a closet liberal--despite the stigma . . . as head of the KGB . . . ." The headline carried the words "closet liberal." Evidently, this provoked the memo writer to propose, not a "witch hunt," but an investigation of who wrote the headline and "to keep an eye on their future activities."

Attached was an item from The Wall Street Journal declaring that the KGB was waging a media campaign on behalf of Mr. Andropov. It cited a earlier leak to The Post of a Kremlin document that concluded Soviet agriculture policy was a mess. The news was not a revelation, except that it was now officially acknowledged. It was, to mix a metaphor, red meat at which an ideologue snapped while conveniently disregarding an obvious question: should the newspaper have ignored it?

Obviously, tha author was too bent on limning the idea that the secret police were out to embarrass Mr. Brezhnev for the benefit of Mr. Andropov, and The Post had been gulled into playing their hand. "The views . . . do not represent those of our analysts. . . (and) thus have no official standing," writes Deputy Secretary of State Walter Stoessel. That's good enough for The Post. The question is: who is taking cowardly advantage of State?

A different communication, signed by AFL-CIO officials Murray Seeger and David L. Perlman criticized The Post--fairly, I think--for its lapse in mid-July when, for the first time, Congress overrode a veto by President Reagan. The legislation, which of course remains the law, affects a copyright issue: non-dramatic literary works, primarily books and periodicals, written in English by authors living in America must be printed and bound in the United States or Canada if they are to enjoy complete copyright protection.

The Post covered the story inadequately, running only a brief UPI item on the House vote July 13 and nothing since. Had the veto been sustained, job losses in publishing and associated industries, according to the Labor Department, would run into six figures. (Labor is working to refine its numbers.) The president saw the legislation as protectionist and as a restraint of free trade. In his veto message he said the "infant industry" justification for protecting printing and publishing is no longer valid. Relief for injury was available under the Trade Act, he said.

The congressional override wasn't even close: 84 to 9 in the Senate, 324 to 86 in the House. Organized labor was jubliant over the outcome. But not so the authors and publishers. The two, who rarely agree on anything short a best-seller, are united now in plans to challenge the constitutionality of the legislation and they have begun circulating letters to all Senate and House members.

Put it all together--a first and overwhelming turnaround of a presidential veto, jobs, authors and publishers, challenges of constitutionality and you've got a pretty good story. The silence of the editors can only mean that Messrs. Seeger and Perlman are right in saying The Post blew it.