One of the Union's fundamental principles is that there should be freedom to move from one member country to another. But anti-immigration parties are gaining ground across western Europe; they could make huge political capital out of potential Ukrainian membership.
第二个原因是移民。欧盟的根本原则之一就是其公民可以在各成员国间自由流动。但反对移民的政党在整个西欧正日渐强势；它们可能将乌克兰潜在的成员资格作为巨大的政治资本。有一种观点还认为更扩大的欧盟只会大而无当。