As Fighting drew closer to Rome, in November 1943 Casati was one of several leading politically active anti-fascists who took refuge in the pontifical seminary at San Giovanni in Laterano. Others included the socialist Pietro Nenni, the Christian Democrat Alcide De Gasperi, the former radical Meuccio Ruini and the democratic socialist Ivanoe Bonomi. These were some of the founder members of the emerging National Liberation Committee (CLN) which became the political face of Italian resistance. The CLN would oversee the transition from Fascism to multi-party democracy after the from (by this point) German military control in June 1944.