However, with the advent of the newly formed
Mauritian Militant Movement (MMM) in the 1970s, PMSD started to lose popularity. It won 23 seats in the pre-Independence
1967 general elections; at the
1976 elections, it retained only 7 (plus an eighth indirectly elected member). Despite this apparent shrinkage in its base the PMSD managed to form part of ruling government from 1976 to 1982 after contracting an alliance with the Labour Party after the 1976 elections. Soon after the 1968 Independence there was disagreement within the PMSD, which formed part of most of the Opposition in Parliament, regarding the growing rapprochement between the PMSD leader
Sir Gaëtan Duval and the Labour leader
Sir Seewoosagur Ramgoolam. As a result, in 1969 a splinter group was formed within PMSD and it was led by
Maurice Lesage and
Guy Ollivry who had been prominent figures of the PMSD. As a result, Maurice Lesage, Guy Ollivry, Raymond Rivet, Cyril Leckning, Clément Roussety and others left PMSD and created their own party, the
Union Démocratique Mauricienne (UDM) which remained active for a number of years thereafter. In the 1990s Gaëtan Duval left PMSD and formed his own splinter party called
Parti Gaëtan Duval. In 1999 Xavier-Luc Duval also left PMSD to form his new party
Parti Mauricien Xavier Duval. In 2000 the PMSD formed part of the historical
MSM/MMM alliance as a minority party. It joined the Labour Party-led
Social Alliance, which included other allies. In 2009 the PMSD merged with the
Parti Mauricien Xavier Duval (PMXD) and retained its old name "PMSD". However
Xavier-Luc Duval became leader and
Maurice Allet became president of the party. The PMSD renewed its focus on the
Mauritian Creole community and remained a close ally of the
Mauritian Labour Party. In the lead up to
elections of 2014, however, the PMSD joined the
Alliance Lepep, a coalition comprising the
Militant Socialist Movement, the
Muvman Liberater, and itself. It won 11 seats. Leading to the
November 2019 elections the PMSD joined forces with its historical ally Labour Party and
Mouvement Jean Claude Barbier (a splinter group from Alan Ganoo's
Mouvement Patriotique) to form an alliance called "Alliance Nationale". This
alliance secured 14 seats in the Parliament. At the
2024 elections the PMSD joined the
MSM, the
Muvman Liberater,
Muvman Patriot Morisien and
Plateforme Militante in the
Alliance Lepep but was defeated. Only one of its candidates,
Adrien Duval, secured a seat in the
Mauritius National Assembly after being nominated as
best loser. ==Election results==