Abstract Moving into the space of tension and contradiction between philosophy and psychoanalysis, I reflect on the spectral way in which Marx and his legacy appear in the Lacanian Left. I explain this spectrality through the impossible mourning of Marxism. I bring in three authors who prescribe mourning here and ignore its impossibility: Özselçuk, Stavrakakis and Alemán. I resort to Benjamin, Lacan, Allouch and Traverso to problematise the Freudian distinction between mourning and melancholy in its application to Marxism. Instead of mourning with its post-Marxist bet, I defend an openly melancholic position based on the militant historical commitment to the dead and what Lacan has represented as the insurmountable directions indicated by Marx. I distinguish three great idealist attempts by the Lacanian Left to overcome the materially insurmountable directions: Laclau’s anti-essentialist discursive postmodernism, Žižek’s pessimistic Lacanian Hegelianism and Badiou’s Jacobin political Platonism. I contrast the Laclauian democratic populist concessions with the Badiouan-Žižekian fidelity to Marxism and communism.