[2] During World War I, Wendler served in the Luftstreitkräfte of the Imperial German army as part of the Royal Prussian Jagdstaffel 17.

Wendler was quite interested in Busch's proposal and subsequently on April 18 sent cables to Berlin which included additional plans for economic collaboration and the formation of an anti-Comintern group composed of Argentina, Bolivia, and Paraguay.

Before the Nazi Foreign Office in Berlin replied to Wendler, they sent him a message on April 13 telling him to be reserved and to end giving advice to the Bolivian government.

State Secretary at the Foreign Office Ernst von Weizsäcker also called on Wendler to avoid any rift between Germany and Busch's government, and that German advisors could be considered later.

He also suggested that Wendler make it clear that the Foreign Office didn't speak for the other anti-Comintern nations, and that any future cables on the matter not be addressed to Adolf Hitler.

This was due to the discovering of a letter allegedly sent from Major Elias Belmonte, who was the Bolivian military attaché in Berlin, to Wendler in La Paz which declared that "the time is approaching to carry out our coup to liberate my poor country from a weak government of completely capitalist inclinations."