The PSD was founded in March 1971 as a secession of the right wing of the Luxembourg Socialist Workers' Party (LSAP) which had a centrist orientation.
[1] The group left the LSAP in opposition to the rising leftist faction in the LSAP, which opposed forming coalitions with the Christian Social People's Party (CSV) and championed coalitions with the Communist Party at communal level.
In total, six of the LSAP's eighteen MPs joined the new party, including Albert Bousser and Astrid Lulling.
In the European election held on the same day, the PSD failed to win a seat, but did beat the Communist Party into fifth place.
Some of its members, including Cravatte, returned to the LSAP, whilst others, such as Lulling, completed their political metamorphosis from left to right by joining the CSV,[1]