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.
The New LEF closed in 1929 due to a disagreement over its leadership between Mayakovsky and Tretyakov, and because of its 'Formalism', which clashed with the emerging Socialist Realism.