From its separation from the Ottoman Empire in 1878 until 1947, Bulgaria was ruled as a constitutional monarchy, with a parliamentary system based on the Turnovo Constitution of 1879. Although that document was one of the most progressive national constitutions in the world when it was written, actual governance of Bulgaria under it was a constant struggle for power among the tsar, the unicameral parliament, and the Council of Ministers. The many political factions that proliferated in the twentieth century added another dimension to this struggle. Parliaments were elected and dissolved for purely political reasons strong prime ministers such as Stefan Stambolov (1886-94) and Aleksandur Stamboliiski (1918-23) ignored parliament to advance their own programs (the constitution had no provision for consultation among government branches, although the Council of Ministers was nominally subordinate to parliament) a succession of weak prime ministers were controlled by the tsar or by political factions such as the pro-fascist Zveno coalition of the 1930s the need to placate the forces of Macedonian irredentism distorted both domestic and foreign politics throughout the post-independence period and no prime minister survived without stitching together tenuous coalitions of parties, many of which had only narrow political agendas. Frequent appeals were made to amend the Turnovo Constitution in other cases, the constitution simply was ignored.

The last arrangement of Bulgarian political forces before World War II was the royal dictatorship of Boris III. Boris devised a system of "controlled democracy" after the short totalitarian regime of Zveno had virtually abolished conventional political parties in 1934 (see The Crises of the 1930s , ch. 1). Boris's system was based on judicious appointments and the balancing of civilian politicians against the army. His purpose was not authoritarian rule but to achieve a temporary centralization of power that would allow Bulgaria to return to stable constitutionality after the chaotic post-World War I period. Boris believed that independent parties would hinder this process, so such parties did not reemerge in Bulgaria under his rule. National elections were not held between 1931 and 1938, and subsequent prewar elections were held under strong government control. In spite of that control, an opposition bloc including the communists gained sixty parliament seats in the 1938 election, compared with ninety-five for Boris's nonpartisan government candidates. In the late 1930s, Boris struggled in vain to form a lasting coalition that could provide solid middle ground between the communist and pro-Nazi factions, both of which rapidly gained support between 1935 and 1940. But when Bulgaria entered the war in 1940, the same "temporary" balance remained in place.

Data as of June 1992