This work is in the public domain in the United States because it meets three requirements:
it was first published outside the United States (and not published in the U.S. within 30 days),
it was first published before 1 March 1989 without copyright notice or before 1964 without copyright renewal or before the source country established copyright relations with the United States,
it was in the public domain in its home country (Chile) on the URAA date (1 January 1996).
Works created in Chile before 1962 are public domain according to Chilean law (this one created more than 70 years ago, by 1952, when it was published in a pamphlet without any attribution to the original author).
Uploaded a work by desconocido from «La Organización Electoral Ibañista». Biblioteca del Congreso Nacional de Chile. 1952 - https://obtienearchivo.bcn.cl/obtieneimagen?id=documentos/10221.1/74926/1/195081.pdf with UploadWizard