Kingdom of Yugoslavia The party was formally founded in 1937 with
Pavle Gregorić as its first general secretary. The reasons for KPJ to have its specifically Croatian branch were partly ideological, partly practical. Croatia, just as
Slovenia, which would have its Communist Party at the same time, was the most industrialised part of the country, with the biggest percentage of
working class in the population, and, therefore, more likely to adopt
communism than rural
Serbia. The other, more practical, reason was in the increased marginalisation of Communists in Croatian political life due to public more preoccupied with ethnic issues and position of Croatia within Yugoslavia (cf.
Croatia in the first Yugoslavia). Territorial aspirations of
Fascist Italy towards Croatian parts of Yugoslavia also presented opportunity for the creation of broad Communist-dominated alliances modelled on
Popular Front. Prior to the formation of the Communist Party of Croatia there was a Croatian-Slavonian Provincial Committee of the Socialist Workers Party of Yugoslavia (Communists) and there was a developed party structure of the Socialist Party of Croatia and Slavonia. Dalmatia had its own structures up to 1937. KPH, just like KPJ, was illegal and, therefore, remained marginalised, especially after the 1939
Cvetković–Maček Agreement and the creation of the
banovina of Croatia within the Kingdom of Yugoslavia. Party's fortunes dramatically changed with the 1941
Axis invasion of Yugoslavia and creation of the
Independent State of Croatia. At the beginning of the
Axis occupation of Yugoslavia,
Aleksandar Ranković was secretary of the Central Committee of the
Communist Party of Croatia. Although KPH had many of its leading figures arrested and killed by new regime, it remained strong enough to form what would become the only truly effective
resistance movement in Croatia – the
Partisans. KPH was based on ideological rather than ethnic grounds and, therefore, had support in both ethnic
Croat and ethnic
Serb areas. This allowed
Josip Broz Tito's Partisans to mount ultimately successful guerrilla campaign. KPH platform of post-war reorganisation of Yugoslavia on federal grounds also attracted many non-Communist Croatians to its cause, especially in the later stages of war.
SFR Yugoslavia In 1945 Yugoslavia was indeed
federalised with Croatia becoming a republic, but its nominal autonomy was of little importance with KPJ being heavily centralised and KPH – renamed into SKH in 1952 – being its integral part. ("little cube"). Former headquarters of the League of Communists of Croatia in
Zagreb. Things began to change in late 1960s with Tito allowing for reformist policies embodied of new generation of Communist leaders. This generation included SKH leaders
Savka Dabčević-Kučar and
Miko Tripalo who would start movement called the
Croatian Spring, advocating for more autonomy of Croatia within Yugoslavia. They advocated against
centralism which disproportionately benefited the eastern parts of Yugoslavia, especially
Serbia and
SR Macedonia. The movement, however, created a lot of ethnic tension and increasing opposition from the more conservative Party members. In December 1971, on the
Karađorđevo conference of the SKJ, Tito publicly distanced himself from Croatian Spring, leading to the end of the movement. Using the alleged Croatian
nationalism as a pretext, SKH was subsequently purged from most of its
liberal and
reformist elements. As a result, SKH in the 1970s became one of the most conservative sections of SKJ and remained interested in maintaining ideological and political
status quo even when other branches of SKJ began to explore new ideas. Because of that, SKH in late 1980s was slow to react when
League of Communists of Serbia under
Slobodan Milošević aimed to reassert internal Serbian interest. SKH began to openly condemn Milošević only in 1989 after Serbian nationalist demonstrations in areas that would later become
Republic of Serbian Krajina. It is estimated that in the 1980s, during its zenith, the SKH had around 300-400,000 members. Subsequent surveys showed that most of the membership left the party in 1990, with only minority remaining active in politics. Of those, majority joined the
HDZ.
Party of Democratic Changes With increasingly apparent prospect of SKH being forced to allow some form of
multi-party democracy and having its power tested on free elections, the party changed policy and quickly adopted a new reformist platform and pushed for the
constitutional amendments allowing first free elections in 1990. In January 1990 the Croatian Party delegation led by
Ivica Račan left the
14th Congress of SKJ, a few hours after the Slovenian Party delegation did so over a row with the Serbian Party delegation. In the next few months, SKH tried very hard to present itself as modern and reformist party, rebranding itself into a new party called the
League of Communists of Croatia – Party of Democratic Changes (
Savez komunista Hrvatske – Stranka demokratskih promjena, SKH-SDP), then to just
Party of Democratic Changes (
Stranka demokratskih promjena, SDP). Those and other changes, however, weren't very convincing to the Croatian electorate and SKH lost power to
Croatian Democratic Union of
Franjo Tuđman. In 1991, it was renamed to
Socialdemocratic Party of Croatia–Party of Democratic Changes (
Socijaldemokratska partija Hrvatske–Stranka demokratskih promjena, SDPH), that would ultimately become the
Social Democratic Party of Croatia in 1993. == Ethno-nationalist issues ==