We model attitude stability and constraint, using a dynamic discrete choice framework for multiple attitudes, to identify influential attitudes within attitude systems. Its value-added includes insights about different sources of (in)stability, the direction of causation between attitudes, and their relative degree of influence; capturing time-invariant individual traits with a multiple factor structure; and addressing the ordinal nature of attitudinal measures, together with heterogeneity in time intervals between interviews, across waves, and people. We examine five core political attitudes concerning how people view the political world and their role in it. Most of their variance reflects infrequently-changing individual characteristics and time-specific effects. Permanent heterogeneity plays a modest role. External efficacy is most influential concerning evaluations of the external political world, while internal efficacy is influential for views on one’s role in politics. Another application examines the role of ideological and party identification on attitudes toward government spending and immigration. The attitudes form a weakly constrained attitude system. Party identification is the most influential, through spillovers to ideological identification. Party and ideological identifications are stable, time-invariant traits explaining most of their variance, with transitory shocks that hint at measurement error and/or expressive responding. Issue attitudes are unstable, driven mainly by transitory shocks.