The New LEF closed in 1929 over a dispute over its direction between Mayakovsky and Tretyakov, and under pressure for its 'Formalism', which jarred with the incipient Socialist Realism.
In 1929, the New LEF closed down due to disagreements among its leaders, specifically between Mayakovsky and Tretyakov, as well as because of its 'Formalism', which did not align with the emerging Socialist Realism.