The unfolding and multilateral capitalist crisis has brought to the fore, once again, the fragility, vulnerability and inherent contradictions of capitalist domination and oppression. At the same time, and despite the flowering of anti-capitalist struggles across the globe, this profound and systemic crisis has revealed the crisis of Left politics, including the radical Left. The impotence of the Left is manifested both theoretically and practically and it is expressed as an inability to propose a radical alternative to the political and economic status quo. This essay discusses the inadequacy of the Left, drawing upon the political writings of Rosa Luxemburg. First, it focuses on her article ‘Stagnation and Progress of Marxism’ and critically examines her views regarding the decay of revolutionary theory. The essay argues that Luxemburg’s analysis raises a number of core questions in respect to our relation with Marx’s theoretical legacy, in the direction of transcending the elements of both dogmatism and nihilism that have marked the course and development of the anti-capitalist movement over the last century. It goes on to examine the limitations of Luxemburg’s approach, which are ascribed to her unsystematic conception of the relationship between theory and practice. Moving on to examine her key political texts, the article argues that, when Luxemburg manages to grasp the internal and reciprocal relation between theory and practice, she insightfully develops a dialectics of revolution, as the result of many interwoven and intersecting dialectical contradictions. Luxemburg’s analysis, then, offers valuable launching points for further discussion of the theory and practice of the anti-capitalist movement and provides important ideas still relevant for the Left and contemporary class struggles.