Most of their members were former Communists or left-wingers displeased embracing Croatian nationalism, the excesses of privatisation and human rights abuses of ethnic minorities.
The first leader of the party was Branko Horvat, noted economist and one of the few Croatian intellectuals to oppose the dissolution of SFR Yugoslavia.
In the 1992 parliamentary elections it turned out that SDU nevertheless enjoyed some degree of support, especially among ethnic Serbs living in government-controlled territories.
Although it failed to break the 2% vote threshold of entry into the Croatian Parliament, the SDU could have hoped to win three seats by fulfilling the constitutional quota of ethnic Serbs in Sabor.
The SDU had some success in the local elections held a few months later, but the biggest boost came to them with parliamentary status gained when Vladimir Bebić [de; hr; sh], a colorful member of Sabor from Rijeka, decided to join their ranks.
[3] The Green Left of Croatia (Croatian: Zelena ljevica Hrvatske) was a leftist party formed in 2001 whose political platform was ecological socialism.