 Following his return to great politics in 1958 he emerged as one of the most prominent monarchists, contributing to shaping of late Francoism in course of works on various key legal structures of the system.Far from political militancy, starting mid-1960s Bau began to press the monarchical cause by advocating adoption of and .Mocked by some critics as himself the best successor to Franco, Bau could have considered his efforts crowned when Juan Carlos was officially confirmed as Franco's successor in 1969, though as late as 1970 he kept fighting the regentialistas, first headed by Muñoz Grandez and than by Valcárcel.