This paper aims to study the argumentative basis on which the prevention of migration is justified and hatred politics is institutionalised in three Mediterranean settings, namely Greece, Malta, and Italy, that were at the centre of the so-called 'refugee crisis' in 2015-2017. Following the rubric of corpus-assisted Discourse-Historical Approach (DHA) to Critical Discourse Studies (CDS), we trace (a) the main meaningful patterns, and (b) discursive and argumentation strategies (topoi) in three balanced corpora of mainstream news portals aligned with centre-right and centre-left political views. Among our main findings, the mobilisation of migrant populations is construed as an extremely polarised issue both in national and EU contexts and claims in favour of its prevention are justified on topoi of danger/threat , numbers and burdening / weighing down .