“I am a communist, but not a member of the Communist Party. Stalin is a first rate Fabian. I am one of the founders of Fabianism and as such very friendly to Russia.”

Responding to a question at his press conference (February 28, 1947); reported in Public Papers of the Presidents of the United States: Harry S. Truman, 1947, p. 191

Peter Longerich, Goebbels: A Biography, New York, NY, Random House (2015) p. 26, “Erinnerungsblätter,” 27, (diary entry: 1924)
1920s

Quoted in Asiaweek, Vol. 5 (1979), p. 28.

Letter to the New York Herald Tribune (29 November 1947)
Context: I am a member of a party of one, and I live in an age of fear. Nothing lately has unsettled my party and raised my fears so much as your editorial, on Thanksgiving Day, suggesting that employees should be required to state their beliefs in order to hold their jobs. The idea is inconsistent with our constitutional theory and has been stubbornly opposed by watchful men since the early days of the Republic.

14 November 1925, The Early Goebbels Diaries 1925-1926, Helmut Heiber, edit. Oliver Watson, trans. Frederick A. Praeger, New York, (1963)
Diary excerpts

Variants: I don't belong to an organized political party. I'm a Democrat.
I belong to no organized party. I am a Democrat.
Source: Will Rogers, Ambassador of Good Will, Prince of Wit and Wisdom (1935), Ch. 9 "Rogers was a lifelong Democrat but he studiously avoided partisanship. He contributed to the Democratic campaign funds, but at the same time he frequently appeared on benefit programs to raise money for the Republican treasury. Republican leaders sought his counsel in their campaigns as often as did the Democrats." ~ P. J. O'Brien

Tim Buck A Conscience for Canada

As quoted in Reprints from the Soviet Press (1977), p. 5