The rise in power of a socialist-minded proletariat immediately after the war prompted a correspondent rise in the old forces of Catholic conservatism, as well as in rural farmers, who quickly won a place on the Federal Council alongside the urban Radicals. At the same time, Switzerland began to take the first overt steps away from its traditional absolute neutrality, voting in 1920 to join the League of Nations – which was headquartered in Geneva, lending both the city and the country a sheen of international prestige that it retains to this day – and yet insisting on an exclusion clause that permitted Swiss adherence to an ill-defined partisan neutrality. The contradiction remained untested until 1935, when the League imposed economic sanctions on fascist Italy after the invasion of Abyssinia: Switzerland (or, more accurately, its right-leaning Ticinese foreign minister, Giuseppe Motta) could not bring itself to punish Italy, and withdrew from the League in favour of a return to absolute neutrality.

As elsewhere, the economic bubble of the 1920s burst in the early 1930s, with a crippling depression halving output, decimating incomes and causing huge unemployment. At the same time, cosy domestic political coalitions were breaking down under the influence of proportional representation, which brought a myriad of economic and political interest groups into parliament. After Hitler’s rise to power in Germany in 1933, sympathetic Nazi “fronts” emerged, gathering support nationwide from right-wing conservatives and hard-hit petty bourgeois merchants who together proposed a root-and-branch revision of the Federal Constitution. But both a devaluation of the franc in 1936 (which boosted Swiss industry in the run-up to war) and a new partnership of liberals and social democrats – who, in the face of spreading fascism, had together consciously abandoned the ideal of class war that had served them so well in the General Strike – were effectively able to sideline these authoritarian movements in favour of continued democratic debate. As war became more and more likely during the late 1930s, the country bolstered its own national institutions, affirming the status of Romansh as a national language, authorizing widespread official usage of Swiss-German as a distancing measure from the High German of the Third Reich, and showcasing homegrown achievements at a National Exhibition in 1939. In addition, it readied its economy and industry for war, passing a series of laws to protect individual earnings should mobilization become necessary, and introducing anonymous numbered bank accounts to protect the savings of German Jews from seizure by the Nazis.