by Yugoslav president Josip Broz Tito as an attempt to silently introduce capitalism, which was illegal under the then-existing constitution. Croatian spring In 1967, when a group of Croatian nationalists published Declaration on the Status and Name of the Croatian Literary Language, Mesić publicly denounced it as a diversionary attack against the very foundations of Yugoslavia and called for its authors to be prosecuted by law. However, in the 1970s Mesić supported the nationalist Croatian Spring movement which called for Croatian equality within the Yugoslav Federation on economic, political and cultural levels. The government indicted him for "acts of enemy propaganda". The initial trial lasted three days in which 55 witnesses testified, only five against him, but he was sentenced to 20 years in jail on charges that he was a member of a Croatian terrorist group. He appealed and the trial was prolonged, but in 1975 he was incarcerated for one year and served his sentence at the Stara Gradiška prison. Return to politics Mesić was elected again in 1990 as a candidate of the Croatian Democratic Union (HDZ) in the first multi-party elections in Croatia after World War II. He became the general secretary of HDZ and later the Prime Minister of Croatia. He served in this post from May to August 1990, when he resigned to become the vice-president of the Socialist Federal Republic of Yugoslavia (SFRY). Presidents rotated annually among the six republics of Yugoslavia. When Mesić's turn came to become president on 15 May 1991, the Serbian incumbent Member Borisav Jović demanded, against all constitutional rules, that an election be held. The members from Serbia and its provinces voted against, and the member from Montenegro abstained, leaving Mesić one vote short of the majority. Under pressure from the international community after the Ten-Day War in Slovenia, Mesić was appointed on 1 July 1991. As Yugoslav President, Mesić also held the position of Secretary General of the Non-Aligned Movement, superseding Jović. In October 1991, at the height of Siege of Dubrovnik, Mesić and Croatian Prime Minister Franjo Gregurić led a relief convoy of forty fishing and tour boats to Dubrovnik. Despite being the head of state of the SFRY, Mesić did not attend many sessions of the collective presidency as it was dominated by four members loyal to Serbia. He was also unable to re-assert control as commander-in-chief of the Yugoslav People's Army, as his orders