One of Glennan’s ([1996]) most prominent contributions to the new mechanist debate consists in his reductive analysis of higher-level causation in terms of mechanisms. In this article I employ causal Bayes nets (CBNs) to reconstruct his analysis. This allows for identifying general assumptions that have to be satisfied to get the analysis working. I show that once these assumptions are in place, they imply (against the background of the CBN machinery) that higherlevel causation indeed reduces to interactions between component parts of mechanisms. I also briefly discuss the plausibility of these assumptions and some consequences for the mechanism debate