If we take psychological findings about political and religious belief systems at face value, we predict that people with more traditional belief systems are more likely to be prejudiced, intolerant, and sensitive to group boundaries compared to people with more liberal or progressive belief systems. This view is consistent with the idea that conservatives tend to be higher on need for closure and more sensitive to threat compared to liberals. We have challenged this prevailing view with our work on the ideological-conflict hypothesis (Brandt et al., 2014). We find that both liberals and conservatives will be equally intolerant of groups with differing political worldviews (Wetherell, Brandt, & Reyna, 2013). The effect has been extended to religious fundamentalism (Brandt & van Tongeren, 2017). The impact of ideology is so strong that we find it can cause intolerance in people who profess to be open to experiences (Brandt et al, 2015). This challenges the traditional social psychological view on both prejudice and political polarization, suggesting that our current models of belief systems are incomplete (for a recent review is Brandt & Crawford, in press).