  How do movements and coalitions which engage with multiple social issues
succeed in cross-issue solidarity, and when do they instead become fragmented?
To address this, the mechanisms of cross-issue interaction have to be
understood. Prior work on opinion dynamics and political disagreement has
focused on single-issue consensus and polarization. Inspired by practices of
cross-issue movement building, we have developed a general model of multi-issue
opinion dynamics where agreement on one issue can promote greater inclusivity
in discussing other issues, thereby avoiding the pitfalls of exclusivist
interaction, where individuals engage only if they agree sufficiently on every
issue considered. Our model shows that as more issues come into play, consensus
and solidarity can only be maintained if inclusivity towards differing
positions is increased. We further investigate whether greater inclusivity and
compromise across issues lead people towards or away from normative truth,
thereby addressing concerns about the non-ideal nature of political consensus.
