In April 1919, the Estonian Constituent Assembly was elected. The Constituent Assembly passed a sweeping land reform expropriating large estates, and adopted a new highly liberal constitution establishing Estonia as a parliamentary democracy. In 1924, the Soviet Union organised a communist coup attempt, which quickly failed. Estonia's cultural autonomy law for ethnic minorities, adopted in 1925, is widely recognised as one of the most liberal in the world at that time. The Great Depression put heavy pressure on Estonia's political system, and in 1933, the right-wing Vaps movement spearheaded a constitutional reform establishing a strong presidency. On 12 March 1934 the acting head of state, Konstantin Päts, declared a state of emergency, falsely claiming that the Vaps movement had been planning a coup. Päts, together with general Johan Laidoner and Kaarel Eenpalu, established an authoritarian regime well known as the "Era of Silence", where the parliament was dissolved and the newly established Patriotic League became the only legal political party. To legitimise the regime, a new constitution was adopted and elections were held in 1938. Opposition candidates were allowed to participate, but only as independents, while opposition parties remained banned. The Päts regime was relatively benign compared to other authoritarian regimes in interwar Europe, and there was no systematic terror against political opponents.