noun
Social Democratic Federation
Proper noun referring to a specific political organization. The exact historical context may vary; in Japan, it often refers to the 社会民主連合 (Shakai Minshu Rengō), a former political party active from 1978 to 1994.
社会民主連合は1978年に結成された。
The Social Democratic Federation was formed in 1978.
Compound of 社会 (society), 民主 (democratic), and 連合 (federation/union). The name directly translates the English 'Social Democratic Federation'.