After being jailed in 1936, Guillén joined the Communist Party the next year, traveling to Spain for a Congress of Writers and Artists, and covering the Spanish Civil War as a magazine reporter.
سال بعد او به عضویت حزب کمونیسم درآمد و به اولین سفر خارج از کشور به مقصد اسپانیا رفت تا در کنگرهٔ هنرمندان و نویسندگان شرکت کند.