In an online experiment with a representative US sample (N=12, 960) we show that increasing the salience of an economic or cultural conflict without providing any news boosts disagreement on a range of political issues by 8-35%. The data support two key predictions of the Bonomi et al. (2021) identity theory of political beliefs. First, polarization amplifies ? through stereotypes ? latent disagreement among the economic or cultural groups standing in salient conflict. Second, there is belief realignment away from no-longer salient groups, causing some people to move across the conservative-progressive divide. These results can illuminate real-world political conflicts and propaganda.