Symbolism and polarization in American public opinion: The case of border security

We explore the effect of political symbols on mass attitudes and partisan identities under conditions of political polarization. Politicians are motivated to select visible, simple, and salient symbols to influence a target audience. Some of the most potent symbols may further polarize attitudes and affect. We test our expectations using the case of border security. Two decades of polls, national panel surveys, and original conjoint experiments in the United States suggest that border barriers have become increasingly partisan over time. A final survey experiment suggests a likely mechanism: exposure to a key symbol (here, a border wall) enhances strong Republican identifiers’ nationalist attitudes. Moreover, increasing the border wall’s salience bolsters ingroup feelings among moderate Republicans and reduces strong Republicans’ warmth for Democrats (the outgroup). Political symbols that divide respondents along salient identity lines contribute to polarization, sometimes creating sharp disagreements alongside consensus in American public opinion.