Social democracy is an ideology of the political Left that emerged from socialism in the earlier part of the twentieth century. While socialism in the strict sense seeks to destroy capitalism (in some cases, by violent means) and to replace it with a different social and economic system, social democracy seeks to subject capitalism to regulation and governmental intervention in order to remedy its alleged deficiencies.
It is generally considered that the international Left split into two distinct camps after the Russian Revolution of 1917. The more extreme faction, which sought to achieve radical societal change through revolution, became known as communism, and was associated with the Bolsheviks while the less extreme faction, which sought to pursue gradual change through the democratic system, became known as social democracy, which was associated with the Mensheviks.
On one definition, social democrats continue to have the ultimate objective of achieving full socialism, albeit by peaceful means. Others prefer to call such people "democratic socialists", and reserve the term "social democrats" for those who would be content with a society comprising a mixture of capitalist and socialist elements (for example, an economy in which a market operates, but with sizeable governmental intervention, and in which enterprise is possible, but business is subjected to high taxes).
Many parties in economically developed nations have espoused social democratic beliefs, including the Labour Party in the United Kingdom, the SPD in Germany, the Social Democratic Parties in Sweden and Finland, and the Australian Labour Party. Social democratic beliefs are also found in parts of the American Democratic Party, and some European and South American Christian Democratic parties have resemblences to social democratic parties.
Since the 1980s, a number of social democratic parties have moved away from the territory of the traditional Left and have accepted greater elements of free-market, capitalistic thought. The principal example of this phenomenon is the British Labour Party under Tony Blair, while other examples include the Australian Labour Party under Bob Hawke and Paul Keating, and the German SPD under Gerhard Schroeder.