The Communist Party had commandeered the cultural high ground of revolutionary Marxism and had imposed its own brand, Marxism-Leninism, as the orthodox version. At the Liberation, the French Communist Party was one of the big three political parties along with the Christian democratic Mouvement Républicain Populaire (MRP) and the Socialist Section Française de l'Internationale Ouvrière (SFIO). It It came to be seen as a patriotic, reformist and 'modern' national party, while its rivals, notably the Socialists, were afflicted with a 'cultural cringe' when faced by the Parti Communiste Français's penetration of working-class milieux. It was the intrusion of the big Communist Party into the French Party system that frustrated the bipolar development in the Fourth Republic. Charles de Gaulle's politics gave the Communist Party the real opportunity to promote the coalition of the left, which it had demanded after 1956.