In September 1917, just ahead of the October Revolution, he served with Nicolae Alexandri, P. M. Morgulis, and V. G. Globa on commission overseeing the Russian parliamentary election at Chișinău (Kishinev).
As a representative of the ethnic-minorities bloc, he was replacing the Armenian Pyotr Z. Bazhbeuk-Melikov, who had failed to attend any of the commission's five previous sessions; Landau was finally made a full member on May 26, on Vladimir Tsyganko's proposal.
Historian Ion Țurcanu argues that Landau's "ably camouflaged" goal was to prevent future legislators from reading the paragraph as barring property ownership by non-Romanians.
[5] Together with Philipp Almendinger, and against Ion Buzdugan, he supported the notion of having decisions vetted by agronomists—more specifically, they asked that any existing model farms be exempt from land redistribution.
[7] On July 24, Tsyganko, as the commission president, noted that he had absented for six consecutive sessions, and had him stripped of his membership; Vladimir Chiorescu replaced Landau on August 2.
[8] After the Bessarabian–Romanian unification had been effected, Landau participated in the life of the larger Jewish Romanian community: in December 1922, he attended a rabbinical conference convened by Jacob Itzhak Niemirower in Bucharest.
[15] In March 1936, during the trial of Petre Constantinescu-Iași and his group of anti-fascists (charged by the authorities with having put up a front for the illegal Communist Party), he appeared as a character reference for co-defendant Paulina Rosenberg.
[16] On December 11, 1938, Petre Andrei, as the Minister of Education and Religious Affairs, appointed Landau to take over as president of the Israelite Community, after his immediate predecessor, Solomon Șur, had been prosecuted as a confidence artist.
Over the following months, the regime, which inherited and enforced antisemitic laws passed in the late 1930s, constructed a conspiracy theory, blaming Jews for the Soviet occupation and for alleged acts of terror.
[19] The allegations were immediately disproved by community leaders such as Horia Carp and Wilhelm Filderman, but, as historian Dennis Deletant writes, "these details [...] had little impact on the officers and men of the Romanian army of 1940.
[23] Landau personally obtained that he be allowed to open a bakery and a hospital (the latter of which was staffed by the Army), and negotiated the conditions of forced labor by the Jewish captives.
With the other Ghetto leaders, Landau addressed an appeal to Constantin Vasiliu, the Gendarmerie commander, attesting that his community was loyal to Romania, and had suffered under Soviet rule, while noting that the mass of the designated deportees were frail people.
As noted by historian Paul A. Shapiro, Landau and the others most likely knew that "death of the deportees" was the desired outcome of Vasiliu's project: "Their appeal for postponement would have made no sense, however, if they had betrayed awareness".