This article analyzes the EU’s December 2004 Brussels decision regarding membership talks with Turkey. While the Brussels Council launched accession negotiations with Turkey, the adopted Framework for Negotiations formulated exceptionally stringent membership terms. This is a puzzle for normative institutionalism because prior to Brussels, Turkey had sufficiently complied with the EU’s liberal democratic membership criteria and systematically engaged in “rhetorical action” to “entrap” the EU in its liberal, inclusionary enlargement discourse. It is argued that the puzzle is explained by how the EU member states’ enlargement preferences played out in an intergovernmental bargaining context when it came to the inclusion of Turkey.