This thesis seeks to explain why the European Union ratcheted up restrictive measures on Myanmar from 1991 until 2010, despite divergent interests of EU member states and the apparent inability of sanctions to quickly achieve the primary objectives of EU policy. This empirical puzzle applies the ‘sanctions paradox’ to the issue of joint action in the EU. It also connects the assessment of policy effectiveness to EU foreign policy-making. The investigation unravels this conundrum through competitive theory testing. The study discovers that EU foreign policy was essentially decided by the largest member states. Since 1996, the UK has fostered a consensus among EU policymakers on a principled common policy, which would induce political reform in Myanmar mainly via the implementation of punitive measures. Hence, noncompliance by the target with EU demands offers a credible, but insufficient explanation of why the EU tightened its sanctions regime. US pressure on EU policy was marginal. The dissertation argues that a ‘normative’ interpretation of liberal intergovernmentalism best solves this puzzle. The EU met domestic pressures for action, although the measures adopted were clearly too inadequate to be effective. Feedback on policy effectiveness did not play a significant role in EU decision-making. EU policy was driven by a consensus to treat Myanmar as a ‘pariah’ state. Ideological motivations have largely outweighed material interests. Normative arguments were necessary to put proposals on the common agenda; yet, decisions ultimately involved ‘cooperative bargaining’ among the largest states. Consensus building was therefore a dynamic process. The policy entrepreneur defined its interests domestically; member states with lower preference intensity generally refrained from opposing its leadership. This thesis thus contributes to the liberal intergovernmental scholarship by proposing a more comprehensive explanation for the drivers and constraints that influence the making of European sanctions.