Often as foreign policy may be the subject of partisan discussion in modern democracies, important international commitments are usually made only with support, or the expectation of support, from the great bulk of the political community. This has surely been the ordinary American and British pattern, labeled bi-partisan, non-partisan, or extra-partisan. We assume that political support extending well beyond the ranks of the party in office is essential for a successful foreign policy, and especially for a substantial military venture. Even the American decision to defend South Korea, while it was necessarily made by the Democratic administration before any apparent political consensus and while it eventually involved the United States in an unpopular war, was never in itself a partisan policy which Republicans as a group refused to support. The one outstanding recent instance of a truly partisan foreign policy is Britain's Suez action of 1956. As the significant deviant case, it provides useful insights into the process by which an alternative to the usual bi-partisan arrangement is developed and conducted. Specific questions concern the making of the Suez intervention decision, the nature of parliamentary support for this decision, the role of party loyalty in maintaining such support, and the significance of partisan opposition.