[4] Within a few years his work was published widely in the New York Yiddish press, under a variety of pseudonyms, including Rinnalde Rinaldine, Dilensee Mirkarosh, Der Royzenkavalir, Doctor Hotzikl, and, finally, Moishe Nadir.
He wrote for an assortment of Communist Yiddish publications including the Frayhayt (Freedom) newspaper and its successor Morgn Frayhayt (Morning Freedom) and the magazines Der Signal (The Signal) and Der Hammer (The Hammer).
When his sharp-tongued theater reviews caused him to be banned from theatrical productions, he resorted to attending plays in disguise.
After a long association with the Freiheit and the Morgen Freiheit, Rayz began to distance himself from the Communist cause with the onset of the show trials in the Soviet Union and publicly broke with the Morgn Frayhayt in the wake of the Molotiv-Ribbentrop Pact.
Rayz discusses his relationship to the Communist Party in his posthumous Moyde Ani (Confessions).