How and why can a political mobilisation prevent what appears to be an economically rational and beneficial government investment? The present paper explores the ways in which both public policy and contentious politics theories can be potentially bridged to answer this question. It suggests ways in which concepts used by public policy theorists such as 'policy windows' (Kingdon, 1984) or 'advocacy coalitions' (Sabatier, 1999) may be useful to understand the emergence of political opportunities or the construction of collective action frames. The case study to be used is the project to export liquefied gas from Bolivia to California, which was promoted by the administration of Gonzalo Sánchez de Lozada in 2002 and was cancelled after civil society groups not only mobilise to resist it, but to demand the resignation of the president