Models and Reality: the Curios Case of the Absent Abstention

We discuss two inter-related puzzling features of the literature on a priori voting power. First, the mathematical model used in virtually all this literature does not recognize abstention as an option distinct from both a 'yes' and a 'no' vote. Second, reallife decision rules of voting bodies - in particular the US legislature and the UN Security Council -  are misrepresented as though they did not allow abstention as a tertium quid. We suggest that these misrepresentations may be examples of what philosophers of science call 'theory-laden observation'.