Here is the beginning of the long article:
ZIONISM is the most stupendous fallacy in Jewish history. I assert that it is wrong in principle, and impossible of realization; that it is unsound in its economics, fantastical in its politics, and sterile in its spiritual ideals, Where it is not pathetically visionary, it is a cruel playing with the hopes of a people blindly seeking their way out of age-long miseries. These are bold and sweeping assertions, but in this article I shall undertake to make them good.This is the earliest formulation I can find of "As-a Jew" to assert that a Jewish state is a bad thing.
The very fervor of my feeling for the oppressed of every race and every land, especially for the Jews, those of my own blood and faith, to whom I am bound by every tender tie, impels me to fight with all the greater force against this scheme, which my intelligence tells me can only lead them deeper into the mire of the past, while it professes to be leading them to the heights.
Zionism is a surrender, not a solution. It is a retrogression into the blackest error, and not progress toward the light. I will go further, and say that it is a betrayal: it is an eastern European proposal, fathered in this country by American Jews, which, if it were to succeed, would cost the Jews of America most that they have gained of liberty, equality and fraternity.
I claim to speak with knowledge on this subject. I have had occasion to know the Jew intimately in all the lands where he dwells in numbers, and to study his problems on his own ground, with the intensity and sympathy which were required by my duty to help in each place to formulate the plans for his immediate assistance. I was born among the Jews of Germany, and by natural association with German Jews in New York, and by repeated visits to Germany, am familiar with their life and problems. As an American of fifty-five years’ residence, as a director of the Educational Alliance and of Mt. Sinai Hospital, as president of the Bronx House and the Free Synagogue for more than ten years, and as one who has traveled on speaking tours from the Atlantic to the Pacific and from Canada to New Orleans on behalf of the American Jewish Relief Committee, I am thoroughly familiar with the American Jews. As American Ambassador to Turkey I came into daily official contact with the Jews from all parts of the Near East, not $1111)’ the Jews of Turkey and of the Turkish Protectorate in Palestine itself, but also the Jews of Egypt, Asia Minor, Greece, Rumania and Bulgaria, to say nothing of the accredited representatives of the Zionist Party in Constantinople. As the head of President Wilson's Commission, which was sent to investigate the alleged pogroms of the Jews of Poland. following the Armistice in 1919, I spent several months on the ground in Poland and Galicia, and talked with thousands of Jews in every walk of life in that greatest center of Jewish population in the world. They told me their troubles; the indignities and the perils they endured; the hatred of their neighbors because of their religion; the deliberate efforts that were being made to stifle their economic life; the political discriminations to which they were subjected; and the social barriers which did not permit them a full life as members of their Community.
I speak as a Jew. I speak with fullest sympathy for the Jew everywhere. ...
Morgenthau was more involved in Judaism than most "as-a-Jews" but his hubris at pretending to know what is best for all Jews is starkly contrasted with the millions of Jews who were slaughtered only twenty years later, partially because Jews like him gave Great Britain the confidence that Jews wouldn't cause a stink when it capitulated to Arab demands not to allow Jews to immigrate to Palestine to save themselves from the Holocaust.
This "expert" first describes why it is literally impossible for Israel to ever prosper economically (in the full British Mandate area), and why Zionism is impossible politically. But then he gives his real reason to oppose Zionism - his certainty that the modern world is a tolerant, accepting place for Jews who can integrate peacefully:
I have often used a figure of speech—it was brought to my mind by a meeting with rugmakcrs in Turkey—as follows: The Jew has been content, in most lands and down the ages, to be the fringe of the carpet, the loose end over which every foot has stumbled, where every heel has left its injuring impression on the disconnected individual strands. What the Jew should do is. to become a part of the pattern of the carpet itself: weave himself into the very warp and woof of the main fabric of humanity; and gain the strength which comes from a co-ordinated and orderly relation to the other strands of human society. His peculiar beauties (his peculiar talents), which in the fringe are soiled and hidden. take on new value when they become part of the main carpet; and they find their glory in lending to the pattern a unique splendor and a special lustre.While he decried Zionism as being utopian and unrealistic, his ideas that Jews would integrate to end antisemitism were even more utopian and unrealistic, as history has shown.
I don't know whether Morgenthau changed his mind after witnessing the Holocaust and the success of the Zionist enterprise, as he died in 1946.
His son was Treasury Secretary for FDR and ended up becoming a strong supporter of Zionism.