WITH a jolt West Germany has been brought back to earth after the tranquillity of its long summer holidays: The nation's most serious spy scandal in at least a decade is unfolding. What the Tiedge case says about the performance of the German secret service is for West Germany's friends to ponder in agonized silence, while its adversaries must be rubbing their hands with glee. Certainly Germany's NATO allies cannot have been assured.
Little is known about the actual number of communist undercover agents working inside West Germany -- a good, if conservative, guess is 7,000.
But if Mr. Tiedge's unchecked freedom of action is anything to go by, the counterintelligence performance of the Federal Republic requires dramatic improvement.
West Germany may possess a much-vaunted social security system and a heart for the downtrodden to boot. But when a nation loses the capacity to differentiate between compassion and professionalism, another kind of security -- national security -- could begin to suffer.
It is safe to assume that this latest scandal will substantially augment Chancellor Helmut Kohl's political problems. It may also have hurt his chances of getting an accord with the Reagan administration to share in the Strategic Defense Initiative (SDI), the visionary proposal for defense against ballistic missile attack. The crucial element in such a deal must be ironclad guarantees that all necessary steps are being taken to protect the sensitivity of the technology transferred. But who in Bonn, at t his moment, could vouchsafe for that without an embarrassed blush?
One cannot imagine a more unwelcome piece of news hitting an unsuspecting public now than the defection of one of the country's leading counterespionage officials to the ``other'' Germany, the German Democratic Republic.
The GDR was the prime focus of Hans-Joachim Tiedge's observation for the last six years, while he worked at the counterintelligence headquarters in Cologne known as the ``office for the protection of the constitution.'' Altogether, Tiedge had worked 19 years in the intelligence community.
How much he may already have divulged to the East German Ministry of State Security has yet to be determined. That he has taken with him the complete knowledge of West Germany's insight -- and is it only West Germany's? -- into the communists' spying operations can, however, be assumed.
Most likely West Germany will have to revamp totally its entire counterespionage network. In a hasty first move a handful of Bonn's most sensitive agents inside East Germany, suddenly imperiled by Tiedge's defection, were reportedly withdrawn to the safety of West Germany.
What makes this case so extraordinary is the unbelievable carelessness with which a man like Mr. Tiedge, burdened with an ever growing number of personal problems known to his superiors -- ranging from alcohol abuse to mounting debt -- was allowed to go on as third in command of counterintelligence service in the Cologne center.
So unsuspecting were his superiors when Mr. Tiedge reported sick from work last Monday morning that it was not until Wednesday evening, when his three daughters reported their father as missing, that an investigation got under way. And this in a country which only days before had discovered that three Bonn citizens -- among them the personal secretary of Martin Bangemann, the finance minister who also is chairman of the Liberal party -- had worked for East German state security and had absconded just ah ead of their likely capture. Could Tiedge, the man whose business it was to counter such activities, have tipped them off?
Thomas Kielinger is the capital bureau chief of the German national daily, Die Welt.