Not since the imperious days of the late Chiang Kai-shek has any foreign beneficiary of the United States dared to treat the American government as disdainfully as Gen. Park Chung Hee, the military dicator of South Korea.

Like the Chinese generalissimo, Park is emboldened by having a "mutual" defense treaty with the United States and, above all, he is fortified by the feeling that he can count on the last-ditch support of out hardcore anti-Communists, who (aided by the China Lobby) successfully sustained Chiang on Taiwan unitl his death.

In short, Gen.Park seems to think he can get away with anything, and so far he has. It's time to disabuse him of this contemptous idea. It's also time to put some distance between South Korea and the United States before we are somehow dragged into another Asian war that coulf be more diastrous for American than Vietnam was.

We originally fought in Korea to save it for democracy, but not it has been debased into a tyranny by its anti-democratic leader. To guard against U.S. disillusionment, however. South Korea initiated a sysematic effort to bribe our Congress into providing continued military and economic support, and now, finally, Gen. Park's government flatly refuses to let American investigators question Tongsun Park, who apparently mastermind the subversion scheme.

President Carter and Congress are not left helpless; there numerous ways they can counter Gen. Park, and the screws can be turned gradually; beginning possibly with a congressional resolution condemning the bribery efforts and demanding the Seoul government's cooperation with Washington's attempted investigation.

That, of course, is not likely to budge Gen. Park in which case the White House could threaten to accelerate the proposed gradual withdrawal of 40,000 U.S. troops from South Korea, now schedeuled over the next four or five years. Since Gen. Park appears already reconciled to the withdrawal, that pressure might fail, too.

Sen. Robert Bryd (D-W.Va.), the Majority Leader, has already pointed to a third and perhaps more effective step that Washington could take, namely killing the $2-billion military-aid package that Seoul demanded as compensation for agreeing to the withdrawal of American forces.

Again, though, there is a catch, for the $13 billion in aid this country has given South Korean over the years has already made it more than a match for North Korea. Only a few months ago the South Korean defense minister assured the national assembly that the South now surpasses the North in military power. He also boasted that his country's defense industries were for superior to the North's and that the latter's military equipment is obsolete.

Perhaps that is what impelled Gen. Park to say on Sept. 30 (South Korea's armed forces day): "We are full of confidence and determination to safeguard our country with our own strength . . ."

The danger to the United States is that South Korea, especially if it gets the extra $2 billion in military aid from us, will become so strong that it may be tempted to start or provoke a renewal of hostilities with North Korea, which could embroil with American troops and activate the mutual-defense treaty we have with Seoul

The treat of denouncing that anachronistic treaty, which can be terminated by either party on a year's notice, may be the administration's best weapon of all in pressuring Gen. Park to restore some semblance of human rights in his country and to cooperate with our effort to get to the bottom of the congressional bribery conspiracy.

The treaty ought to be terminated in any case, for it serves the interest of only one party - South Korea. It is a "mutual" pact in name only: From whom is South Korea protecting us? Washington should free us from this reckless obligation while it can do so honorably. The alternative is to keep on risking involvement in another Asian war or to go back on our word after the shooting starts.

The American public has already made it clear that it will not support such a conflict, treaty or no treaty. The most recent national poll showed 65 per cent against American intervention in a second Korean war, with only 14 per cent approving.

That may have prompted Barry Goldwater, the usually belligerent senator from Arizona, to call for a "new American realism" toward Asia. "There are 40,000 American soldiers in South Korea," he said, "and we are pledged to preserve the intergrity of that country." Despite this, he added, "I have great reservations whether or not we would."

Former Secretary of State Dean Acheson was criticized for saying, prior to the Korean Was in 1950, that that country lay beyond America's defense perimiter. Several months ago, however, publication of classified diplomatic papers revealed that the Joint Chiefs of Staff shared that view.

In a top-secret report of the National Security Council in 1949, which called for early withdrawal of American troops from Korea, the Chiefs said that the United States "has little strategic interest in maintaining its present troops and bases in Korea."

Today, almost three decades later, the former CIA station chief in Korea, Donald Gregg, says that the government of Gen. Park is inherently unstable and, therefore, jeopardizes U.S. interests there. He is also quoted as having said that the best thing Gen. Park could do for his country was to resign and open the way for a peaceful change of government. Who in this country would disagree?.