Neumann was indispensable but unsettled with the Institute for fear of disputes.

Evidence

But Neumann was too hot a property for the Institute’s directors. He was currently bearing the main burden of the Institute’s academic work in New York, and was in charge of the efforts to find new openings with Columbia and with research foundations, as Horkheimer stated in a letter to Lowenthal in October 1941. If any of his efforts should, against their expectations, be successful, Neumann would doubtless become a kind of director of the New York branch of the Institute. For fear of disputes, the settlement of the Institute’s relations with Neumann was put off once again. — Rolf Wiggershaus, The Frankfurt School, 1217