We examine contemporary Monday Demonstrations ('Montagsdemos') in Eastern Germany, exploring their role at the intersection of social justice activism, peace movements, and anti-establishment politics. Based on field research at protests in Gera and Chemnitz, we analyse participants' grievances, motivations, and ideological positions. Russia's war of aggression in Ukraine challenges democracies and societies in reunified Europe. Against this backdrop, the 'Montagsdemos' have evolved into a convergence point for diverse actors, from left-wing social justice advocates to far-right extremists opposing Germany's energy policies, NATO alignment, and economic strategies. Drawing on 195 interviews, we examine how these protests reflect broader challenges to liberal democracy, including democratic representation, protest dynamics, and political polarisation. Our findings show that these demonstrators are driven by anti-establishment attitudes, critiques of Germany's foreign policy, and opposition to liberal democracy. Scepticism towards the German Green Party is widespread, with many blaming it for economic and geopolitical challenges, alongside broader criticism of U.S. influence and perceived warmongering tied to the Ukraine conflict. The 'Montagsdemos' illustrate evolving cleavages in German and European politics, particularly the rise of an illiberal opposition to globalisation, climate change adaptation policies, and perceived elite rule.