Abstract A significant proportion of human reasoning is systematically biased, a fact that sits uneasily with argumentation theory’s methodological commitment to the principle of charity. Traditionally, the principle requires arguments to be reconstructed as plausibly and rationally as possible, which conflicts with the definition of cognitive biases as irrational. The aim of this paper is to show that we can and should integrate cognitive biases into argument reconstruction. Firstly, we demonstrate both the ubiquity and societal consequences of biased reasoning. We then articulate a trilemma for argument analysis: (i) exclude biased reasoning from reconstruction, (ii) redefine it as rational, or (iii) abandon the principle of charity. We argue that this trilemma can be resolved by adopting a nuanced understanding of charity that puts sufficient emphasis on the descriptive standard of accuracy alongside the normative standard of plausibility. By properly pursuing these dual aims, we can account for instances of biased reasoning in argument analysis in terms of the underlying mental states and processes. By taking the effect of the in-group bias in climate skepticism as an instructive example, we present one way of integrating cognitive biases into argument analysis by reconstructing instances of biased reasoning as arguments. The aim of such reconstructions is not to vindicate biased reasoning as epistemically sound, after all, but rather to make its justificatory structure transparent and discussable.