As in the case of World War I, Bulgaria fought on the losing German side of World War II but avoided open conflict with the Russian/Soviet state. Again the strains of war eroded public support and forced the wartime Bulgarian government out of office. But World War II heralded a drastic political change and a long era of totalitarian governance.
Having failed to remain neutral, Boris entered a passive alliance with the Axis powers. The immediate result was Bulgarian occupation (but not accession) of Thrace and Macedonia, which Bulgarian troops took from Greece and Yugoslavia respectively in April 1941. Although the territorial gains were initially very popular in Bulgaria, complications soon arose in the occupied territories. Autocratic Bulgarian administration of Thrace and Macedonia was no improvement over the Greeks and the Serbs; expressions of Macedonian national feeling grew, and uprisings occurred in Thrace. Meanwhile, the Germans pressured Bulgaria to support the eastern front they had opened by invading the Soviet Union in June 1941. Boris resisted the pressure because he believed that Bulgarian society was still sufficiently Russophile to overthrow him if he declared war. After the Japanese attack on Pearl Harbor ended United States neutrality, Bulgaria declared war on Britain and the United States, but continued diplomatic relations with the Soviet Union throughout World War II. Acceleration of domestic war protests by the BCP in 1941 led to an internal crackdown on dissident activities of both the right and left. In the next three years, thousands of Bulgarians went to concentration and labor camps.
The German eastern front received virtually no aid from Bulgaria, a policy justified by the argument that Bulgarian troops had to remain at home to defend the Balkans against Turkish or Allied attack. Hitler reluctantly accepted this logic. Boris's stubborn resistance to committing troops was very popular at home, where little war enthusiasm developed. Nazi pressure to enforce anti-Jewish policies also had little support in Bulgarian society. Early in the war, laws were passed for restriction and deportation of the 50,000 Bulgarian Jews, but enforcement was postponed using various rationales. No program of mass deportation or extermination was conducted in Bulgaria.
Data as of June 1992