ROSSEM was a Belgian libertine political party founded in 1991 by the maverick Flemish businessman and writer Jean-Pierre Van Rossem. The acronym 'ROSSEM' stood for 'Radicale Omvormers en Sociale Strijders voor een Eerlijker Maatschappij" which can loosely be translated as "radical reformists and social fighters for a fairer society".
The party participated in the 24 November 1991 elections for the Belgian national parliament. It scored surprisingly well for a non-mainstream party, achieving 3.2% of the vote which entitled it to three seats in the lower house and one in the senate.
Initially, Van Rossem could not take up his seat as he was arrested a few days before the elections following allegations of major financial fraud. He was eventually sworn in on 7 January 1992. Another parliamentarian for ROSSEM was Jan Decorte, a Flemish stage actor and director, who broke with Van Rossem following the 1993 incident (ref. below) and continued as an independent.
In 1993 Van Rossem again courted controversy by shouting 'Vive la république' during King Albert II's oath ceremony following his succession to the throne. Later that year, the party collapsed due to infighting amongst its members, and did not contest the next election.