By late 1923, Banu was noted for his opposition to the new PNL establishment, whose most prominent figure was Vintilă Brătianu; unlike his colleagues, he did not believe in the goal of "crushing" the opposition, at the time led by the Peasants' Party. Resigning from the Ministry in November, to be replaced by Alexandru Lapedatu, Banu still served in the Senate, but largely withdrew from public life. His articles and musings were being still published in "Adevărul", "Convorbiri Literare", and "Cele Trei Crișuri". In 1927, celebrating the golden jubilee of Romanian Independence with conferences at the Bucharest Atheneum, Banu outlined his liberal critique of the conservative ethos, turning against "reactionary" cultural figures such as Caragiale, Mihail Eminescu, and the "Junimea" circle. Such themes were also explored in his lectures, recorded by Radio Romania in 1929 and 1933. As Caragiale scholar Șerban Cioculescu noted at the time, Banu's "effete phraseology" and "cliche vocabulary" encased his resentments against conservative intellectuals, who had exposed and satirized the "characteristics of practical liberalism".