I N T R O D U C T I O N T O V O L U M E 1 4 l x v French were “a healthy people as they have overcome the dangers of victory so quickly,” and to Besso that the French were “the lesser evil” in comparison to Ger- many (Docs. 249, 253). Later that summer he wrote to Langevin that he thought the political atmosphere in Europe had improved, but that “the long-held negative attitude still continues to have an effect among many nations” (Doc. 284). In Sep- tember 1924, he once more expressed support for federalism, writing that a united states of Europe was a necessity if the continent was to preserve its significance (Doc. 322). Disappointed by his failure to establish a national German commission for the League of Nations, in January 1925 Einstein complained to Lorentz that “the epi- demic disease of the Europeans lies in the cerebellum and therefore cannot be fought against with arguments” (Doc. 416). In Argentina he published another ar- ticle in favor of European federalism, stating that throughout their history, Europe- ans have “cross-fertilized” one another: “[…] in spite of its national idiosyncrasies and selfishness, Europe leads a common and international existence therefore, bel- licose entanglements have to seem foolish, one wants to say suicidal.” In his view, nearly all leading intellectuals in Europe had been pacifists, and many had been in favor of unifying European states. He condemned the “ridiculousness of a misera- ble patriotism.” The war had reawakened the pan-European ideal, which ought to rule the future of Europe “if the continent is not going to dig its own grave.” He also understood that Europe could not survive without American involvement, and called on all American countries to join the League of Nations (Einstein 1925j, 1925p [Doc. 463]). More concretely, given Germany’s precarious relations with the Allies, the rup- tured ties between the European scientific communities continued to affect his con- nections and decisions. In July 1923 Einstein reluctantly agreed to attend the annual meeting of the Deutsche Physikalische Gesellschaft, which, for nationalis- tic reasons, was to be held in Bonn, then under French occupation. Although he disagreed with the organizers’ intention to make a political point out of the confer- ence’s location, he nevertheless condemned the occupiers as “military layabouts” who “parasitically live off others.” He was not enthusiastic about participating, but felt obligated to do so out of a sense of solidarity (Docs. 74, 118, 120). The follow- ing month he informed Lorentz that Arnold Sommerfeld had convinced him not to attend the upcoming fourth Solvay Congress in Physics since no other German col- leagues were to be invited. He asked that no invitation be issued to him, so as to avoid the awkward situation of having to decline (Doc. 102). International collaboration in scholarly publications also engaged Einstein. In late 1924, Otto Blumenthal, editor of the Mathematische Annalen, asked Einstein to help him obtain contributions from Paul Painlevé and Jacques Hadamard to the