This article analyzes the argumentative potential of the use of metaphors in media and political communication. The different levels in which the evaluative content of metaphor crystallizes are examined and their articulation is illustrated by means of a corpus of political and journalistic metaphors related to the Spanish "peace process" (2006-2007). This corpus-based study yields interesting conclusions as regards the persuasive use of metaphors in different genre (news and argumentative texts) and the nature of the fields of intersection between the metaphoric argumentation found in media and political communication.