Politicians and media frequently invoke immigration threats to shape public opinion. But how do outgroup threat frames affect norms of citizenship, including behavior, liberal value commitments, and national belonging? This paper presents evidence from an embedded vignette survey experiment in three immigrant-receiving societies: United States, United Kingdom, and Germany. I find immigration threats are filtered through partisanship in polarized settings, and asymmetrically affect norms of “good citizenship” among individuals on the partisan left. However, we see variation within this group: Democrats (US) de-value norms of behavior, like voting and being informed, while Labor supports (UK) repudiate liberal norms like tolerance and rally around national belonging. By contrast, in Germany, we observe more consensus in citizenship norm responses. The strong effect of immigration threat framing on the partisan left brings our attention to the strategic use of immigration discourse to move traditionally sympathetic citizens away from democratic civic ideals.