On the night of 12 June 1945, roughly two hundred rabbis gathered at New York's Hotel McAlpin under the Union of Orthodox Rabbis of the United States and Canada, formally declared Rabbi Mordecai Kaplan outside the bounds of the Jewish religion, and burned a copy of his prayer book as part of the ceremony. Book burning as a form of religious censure has ancient precedent in Jewish legal history, and the assembled rabbis were consciously invoking that precedent rather than improvising a punishment.
Kaplan learned what had happened only afterward. He had been given no hearing before the herem was declared, and his public response was blunt: he compared the burning to what he called the Nazi practice of destroying books, a charge aimed squarely at the symbolism the Orthodox rabbis had chosen and clearly intended to sting. The Jewish Telegraphic Agency reported the episode the following day, preserving both the ceremony's own account of itself and Kaplan's counter-framing in the same contemporaneous record.
What actually provoked this response was not a fringe pamphlet but the founding prayer book of an entire movement, the liturgy Kaplan had written to put his Reconstructionist theology into weekly practice. The severity of the reaction is itself evidence of how seriously Orthodox authorities took the challenge a rewritten Sabbath service posed, not to any single congregation, but to what counted as legitimate Jewish worship at all.