Despite expectations of a landslide, the French public barely approved the Maastricht Treaty in 1992. Traditional explanations for the surprise outcome that rely on socioeconomic conditions, partisanship, regional characteristics, and domestic issues are inadequate. Analysis based largely on the French National Election Study of 1995 shows that the voters were largely concerned with foreign policy. Citizens who were friendly to Germany and supportive of the European Union greatly favored the treaty. French nationalists and those possessed of strong anti-immigrant sentiment were vehemently against it. These disparate views, united in their concern about the sovereignty of France, dominated the Maastricht vote and appear to have persisted in the European Union Constitutional referendum of 2005.