In January of 1989, Müller and ten other activists were arrested after distributing handbills calling for a demonstration to demand freedom of expression, assembly and association and freedom of the press. The demonstration to take place in Leipzig on the anniversary of the murder of Rosa Luxemburg. The activists’ release a week later, following protests in the GDR and abroad, stood out in stark contrast to the treatment of those arrested in connection with the previous year’s demonstration in Berlin.

The grassroots groups in Leipzig found ways to create a public stage through creative forms of protest. On World Environment Day in 1988, they organised the Pleiße Remembrance March along the polluted and sealed over Pleiße river in central Leipzig. Müller was also involved in this work. During the second Pleiße march, in 1989, there were arrests. Groups began to organise non-voter demonstrations after the opposition presented evidence of the falsification of the results of local elections in May 1989. A street music festival entitled “Freedom with Music”, organised by Jochen Läßig and Katrin Hattenhauer, was held on 10 June. The state responded to events like these with brutal arrests and severe fines. At a demonstration held the end of the Saxon Church Day in July, Müller, Christoph Motzer and Kathrin Walther carried a banner with the word “democracy” written on in it German and Chinese – a reference to the Tiananmen Square Massacre of 4 June 1989. The SED had expressed support for Beijing’s bloody response to the protests. Around 1000 Church-Day attendees joined the demonstration, making it the largest protest Leipzig had seen since the “Beat-Demo” by young people in 1965. With several Western journalists present, there were no arrests. Lawyer and Stasi “unofficial collaborator” Wolfgang Schnur was able to prevent the display outside of Church premises of a banner protesting election fraud created by Katrin Hegewald and Stephan Weiß from Berlin.

The Monday “prayer for peace” in Leipzig’s Nikolaikirche was a regular meeting point. The groups obtained support from a few clergymen, such as Christoph Wonneberger, Klaus Kaden, Rolf-Michael Turek and the Catholic cleric Hans-Friedrich Fischer. When, in the summer of 1988, Superintendent Friedrich Magirius excluded the politically motivated groups from involvement in planning the peace prayers, Müller handed out cloths representing gags on which was printed the word “Redeverbot” (ban on speech) and left informational material on the forecourt of the church. This led to the development of a “Speakers’ Corner” for a few weeks in the autumn of 1988. In April of 1989, the groups were permitted to take part in the peace prayer again; police would come in force to contain the attempts to hold demonstrations on Mondays after the prayer meetings.

One week after a demonstration was held during Leipzig’s Autumn Fair under the slogan “for an open country with free people”, the state reacted with large numbers of arrests (including those of Katrin Hattenhauer und Carola Bornschlegel). This triggered a wave of solidarity in Leipzig and other cities as well. An information group active in the congregation of St. Lukas Church, which included Thomas Rudolph, Kathrin Walther, Rainer Müller and the Rev. Wonneberger, organised protests and documented the state’s brutal abuses at the subsequent Monday Demonstrations, which were growing rapidly – there were more than 8000 participants at the demonstration on 25 September. In response to the violent indignities suffered by demonstrators arrested in East Berlin and other cities on 7 and 8 October and quotations in the press on 9 October of communist task force commanders threatening to adopt the “Chinese solution”, Müller and other Leipzig figures drew up document that was signed by several opposition groups. The document appealed directly to state task force troops: “Do not to respond to peaceful with violence! We are one people!” Leipzig opposition figures and theology students distributed around 20,000 handbills with this text. It wasn’t until weeks later that this same call began to be coupled with the call for German unity as well.

In 1990, Rainer Müller was on the GDR speakers’ council of the Initiative for Peace and Human Rights (Initiative Frieden und Menschenrechte, IFM), which merged with other groups to form Alliance ‘90 (Bündnis ’90) in 1991. In 1993, he and other Leipzig figures left the alliance, which was merging with the West German Green Party and joined the New Forum (Neues Forum).

Today, Müller works as a historian and lives with his partner and four children in Leipzig, where he studied medieval and modern history in the 1990s. He is active for the New Forum at the local and national level, works in various social policy groups and heads IFM-Archiv Sachsen e. V., an association that researches the history of resistance to the SED dictatorship.