Having announced a "rebuke" to U.N. Ambassador Andrew Young, President Carter finds himself in a political trap built by two immuatable facts that are fully appreciated though never publicly admitted in his administration.

Fact No. 1: Young's interview with Le Matin of Paris, equating oppresed Soviet dissidents with U.S. "political prisoners," was no aberration , but followed a pattern begun when he came to the United Nations. Instead of newsmen enlarging Young's every utterance as apologists claim, they have ignored most of his heavy rhetorical output. So it is fair to expect more of the same, although slightly softer. That happened the very day after the president's "rebuke" when Young reiterated to the International Herald Tribune the essence of his Le Matin interview.

Fact No. 2 : No Carter-administration official is more fireproof than Young. White House daydreams about easing him out were quickly obliterated by massive support for him from blacks. Carter political advisers concluded that to sack Young would risk the president's black constituency, still strong while other support crumbles.

The president, therefore, is trapped by Andy Young. While Young's mere presence antagonizes many voters quite apart from the likelihood of his future philosophizing), Carter dare not sack him. Having acted in haste to name a glamorous U.N. envoy, the president can repent in leisure about a no-escape dilemma.

"Outraged" was the most common word describing the reaction to Young's Le Matin interview among State Department officials, even McGovernite liberals. Yet what Young said was identical in substance to what he has been saying for 18 months, usually without anybody's taking notice.

"I see my country as vulnerable as anybody else's around the table," Young commented last year as he addressed the U.N Human Rights Commission (representing the world's most barbarous despotisms). While the Kremlin persecutes dissenters, Young pointed out, "many of our own students were shot down on their campuses."

But in describing the communist world, he sometimes voices the axiom of Radio Moscow and Radio Havana that political freedom is subordinate to economic security. "For most of the world," he declared on Human Rights Sunday, last December 11, "civil and political rights come as luxuries . . . that are far away in the future." In the Soviet Union, he added, "human rights are essentially not civil and political, but economic."

While Young is unforgiving about right-wing dictatorships, he is lenient toward communist tyranny. This climaxed in May 1977 in Mozambique, a Marxist regime with 100,000 citizens in forced-labor camps. "East and West alike look to this nation with new hope and with new courage," Young said. While welcoming communist Vietnam into the United Nations by praising its "struggle for independence," he ignored repression and genocide in the new Indochina.

Those quotations and many more are recounted in a forthcoming Commentary article by Carl Gershman, executive director of the Social Democrats. He comments on "Young's apparent lack of commitment to political freedom and his ability to turn a blind eye to oppression" by Third World "progressive" regimes. Gershman reaches his conclusion: "Young finds himself today for the most part on the side not of the oppressed but of the oppressors."

Since Young's philosophy conflicts with stated U.S. foreign policy, why is he not removed? The reason given at both the State Department and White House is his successful conduct of policy on Africa, particularly negotiating a peaceful settlement in Namibia (South-West African). In fact, the Namibian question is far from settled, and preliminary success should not be attributed to Young. Prospects for peaceful transition to a pro-Western regime in Rhodesia have not been helped by Young's rhetoric, most recently unsubstantiated charges that Ian Smith's government was behind the massacre of missionaries. Bishop Abel Muzorewa, the moderate black Rhodesian leader, arrived in Washington last weekend furious over Young's slanders.

The real reason Young is fireproof is found not on the African continent but on the House floor. "You heard as well as I did what John Conyers said," a White House aide told us. When Rep. Conyers (D-Mich.) and other members of the Black Caucus took the floor July 13 to defend Young, they implicitly threatened the president if he changed U.N. ambassadors. Pro-Young rallies of blacks followed around the country that weekend. Some Carter officials talk of bringing Young into the White House or sending him abroad as an ambassador, but most feel they are stuck with him at Turtle Bay. Any move, they fear, might deface the extraordinary seal of approval from Young attesting that Jimmy Carter is "free of racism." They are left with only hope. While the president's men cannot expect Andy Young to change his world view, they can hope what he says will be ignored by the media as it often has been in the past.