Recent research indicates the need to understand how threats operate at a local level. In the wake of Brexit’s significant impact on Ireland’s political, economic, and social climate, the present research investigated whether information about economic threat posed by this political event affect political preferences in the Republic of Ireland, as well as national identity and boundaries of the national group ( N = 267). We experimentally manipulated perceived economic threat posed by Brexit using fictitious information and assessed political preferences for a ‘United Ireland’. Additionally, we examined the impact of this economic threat for strength of national identification, as well as the boundaries of the national community, measured by civic and ethnic nationalism. We also assessed participants’ agreement with the manipulated information about Brexit as a moderator of these effects. Results indicated that threatening information about Brexit goes along with more support for Irish unity the more participants’ agree with the information and reduces support the more participants’ disagree. There was no effect of threat on national identification or civic and ethnic nationalism. The discussion highlights the implications for constructing threats in political messaging and offers important insights into preferences for Irish unity within the evolving Brexit context.