section_path: History/Between the World Wars (1918–1941)
section_name: Between the World Wars (1918–1941)
paragraph_text: Between the World Wars (1918–1941)
  
  Following the First World War, Hungary underwent a period of profound political upheaval, beginning with the Aster Revolution in 1918, which brought the social-democratic Mihály Károlyi to power as prime minister. The Hungarian Royal Honvéd army still had more than 1,400,000 soldiers when Károlyi was installed. Károlyi yielded to U.S. President Woodrow Wilson 's demand for pacifism by ordering the disarmament of the Hungarian army. Disarmament meant that Hungary was to remain without a national defence at a time of particular vulnerability. During the rule of Károlyi's pacifist cabinet, Hungary lost control over approximately 75% of its pre-war territories (325,411 square kilometres (125,642 sq mi)) without a fight and was subject to foreign occupation. The Little Entente, sensing an opportunity, invaded the country from three sides— Romania invaded Transylvania, Czechoslovakia annexed Upper Hungary (today's Slovakia), and a joint Serb - French coalition annexed Vojvodina and other southern regions. In March 1919, communists led by Béla Kun ousted the Károlyi government and proclaimed the Hungarian Soviet Republic (Tanácsköztársaság), followed by a thorough Red Terror campaign. Despite some successes on the Czechoslovak front, Kun's forces were ultimately unable to resist the Romanian invasion; by August 1919, Romanian troops occupied Budapest and ousted Kun.
  
  In November 1919, rightist forces led by former Austro-Hungarian admiral Miklós Horthy entered Budapest; exhausted by the war and its aftermath, the populace accepted Horthy's leadership. In January 1920, parliamentary elections were held, and Horthy was proclaimed regent of the reestablished Kingdom of Hungary, inaugurating the so-called "Horthy era" (Horthy-kor). The new government worked quickly to normalise foreign relations while turning a blind eye to a White Terror that swept through the countryside; extrajudicial killings of suspected communists and Jews lasted well into 1920. On 4 June 1920, the Treaty of Trianon established new borders for Hungary. The country lost 71% of its territory and 66% of its pre-war population, as well as many sources of raw materials and its sole port at Fiume. Though the revision of the treaty quickly rose to the top of the national political agenda, the Horthy government was not willing to resort to military intervention to do so.
  
  The initial years of the Horthy regime were preoccupied with putsch attempts by Charles IV, the Austro-Hungarian pretender; continued suppression of communists; and a migration crisis triggered by the Trianon territorial changes. The government's actions continued to drift right with the passage of antisemitic laws and, because of the continued isolation of the Little Entente, economic and then political gravitation towards Italy and Germany. The Great Depression further exacerbated the situation, and the popularity of fascist politicians increased, such as Gyula Gömbös and Ferenc Szálasi, promising economic and social recovery. Horthy's nationalist agenda reached its apogee in 1938 and 1940, when the Nazis rewarded Hungary's staunchly pro-Germany foreign policy in the First and Second Vienna Awards, peacefully restoring ethnic-Hungarian-majority areas lost after Trianon. In 1939, Hungary regained further territory from Czechoslovakia through force. Hungary formally joined the Axis powers on 20 November 1940 and in 1941 participated in the invasion of Yugoslavia, gaining some of its former territories in the south.