In this study, we will present an analysis of discourses on the boundary between opinion expression and hatespeech, based on a corpus of online discourse of Belgian French-speaking politicians. Our corpus consists of the Facebook and Twitter productions from leading politicians from all major parties, which were collected one month right before and one month during the 2019 electoral campaign for the regional, national and European elections on May 26th 2019. While discourses falling within the legal qualification of hatespeech are extremely rare in this corpus, we will analyze the productions that are on the boundary between opinion expression and hatespeech, engaging in polarizing and stereotyping representations of certain communities based on criteria related to ethnicity, religion and sexual orientation. We look into the linguistic strategies that are used to construe these polarizing representations, such as the use of deictics, generalization, metaphorical language use, and the construction of agentivity and intentionality (i.e. the representation of certain actions as intentional deeds, thus construing e.g. an immigrant group as willingly harming the local population). We both analyze the use of these individual strategies in our corpus and show how they are combined in creating a discourse that represents these communities as a threat. Finally, we will also discuss to which extent there are differences between discourse produced before and during the electoral campaign. In doing so, we show how a detailed discursive analysis based on a corpus of contemporary online data can contribute to a better understanding of the general public debate and of people's conceptualisations concerning these communities.