Ideal theory faces a paradox. The ‘capacity of guidance’ is an important feature of most normative theories, but ideal principles of justice are not well suited to guide action in non-ideal circumstances. This charge presses us to seek plausible avenues to connect ideal values with the non-ideal realisation of justice. The objective of this paper is to introduce an analytical framework and present a case study in support of what I call the ‘reflective integration thesis’. The thesis states that: if (...) we wish to formulate principles of justice that can guide action in non-ideal circumstances, we need to integrate ideal and non-ideal theory, and the way to integrate ideal and non-ideal theory is by seeking reflective equilibrium between these levels. Taking climate justice as a model, this paper will explore the features of a non-ideal theory of justice, thereby providing insights about the structure of an action-guiding theory. It will show that, in order to guide action, our ideal principles of climate justice need to be reformulated in the light of real-world considerations, which we only obtain by integrating the relevant empirical work on the matter. (shrink)