Mäkelin wrote several important texts: Finnish Labour Party's 1903 Forssa Declaration on Universal Suffrage; the Red Declaration during 1905 general strike that demanded dissolution of Senate of Finland and universal suffrage, political freedoms, and abolition of censorship. 18 July 1917 Socialist-majority Parliament accepted (pro 135, against 55) a law crafted by his committee to transfer the ultimate political power in Finland to Parliament of Finland. The Russian Provisional Government chose to ignore the law and dissolved the Parliament of Finland.
After the Finnish Civil War he was captured by the Whites and sentenced to death, later converted to life sentence. A general pardon was granted 1922 and Mäkelin was released. After division of Finnish Social Democratic Party, he chose the Communist side. Due this he was again arrested in August 1923 and committed suicide in prison in September 1923.
6000–7000 people took part in his funeral in Oulu. A street was later named after him.