The opportunities and limitations of Open Marxism (OM) for understanding structure and agency in capitalist society and political economy have been subject to various debates. Critics assert that, in spite of an auspicious commitment to keeping struggle in view, OM as a theoretical approach nonetheless tends to dialectically intertwine structure and agency in such a way that the latter disappears into the former. Critics argue that this presents an unassailable challenge for empirical work and practical politics. Only its further development will keep OM from closing up. This can be done by using Radical Historicism, a methodological intervention that treads a different path through the dialectical unity of agency and structure, avoiding closure. As a potential modification of OM geared toward making it methodologically operational, Radical Historicism provides a philosophical foundation for both empirical research agendas and political praxis.