Law on the Protection of the State

The Law on the Protection of the State (Serbo-Croatian: Закон о заштити државе, Zakon o zaštiti države) was a piece of legislation enacted in the Kingdom of Serbs, Croats and Slovenes (Yugoslavia) in August 1921. The law was proposed by the government, then adopted in the Parliament on 1 August, and came into force on 2 August. This law banned the Communist Party of Yugoslavia (CPY), stripped all communist MPs of their seats, and defined any kind of "communist propaganda" as a crime against the state punishable with the death sentence. All the communist MPs were immediately indicted by the court and some of them arrested and sentenced to prison sentences. All communist mayors and city councilors were deposed and most of them arrested too.

At the time of the adoption of the law, the CPY was the third largest parliamentary group with 58 seats, and had won municipal elections in many municipalities, including the two largest cities of Belgrade and Zagreb. The state's attitude towards the communists was already negative since the communists have organized several large-scale strikes and protests in the previous 2½ years. In December 1920, the government enacted the Obznana, a semi-official decree that outlawed communist propaganda and communist-affiliated trade unions, but did not outright ban the CPY. This only led to increase in violence as some communists organized several political assassinations. The government accused the leadership of the CPY for the violence, although they denied participation and vowed to respect legal forms of action. The government, which was dominated by the Radical and Democratic parties, declared the CPY a subversive and terrorist organization that needs to be banned in order to protect the state from violent overthrow.

The law was quite effective and led to the almost total destruction of the CPY and the Communist League of Yugoslavia (SKOJ), which both became illegal and went underground. In 1924, the provisions of the law were also applied to the Croatian Republican Peasant Party after they joined the Bolshevik-organized Peasant International.