When does a Senator primarily vote according to their personal beliefs, potentially opposing their constituents?

In the context of U.S. Senate voting behavior, the term "trustee" describes a scenario where a senator makes decisions based on their personal beliefs and judgment, rather than strictly following the preferences of their constituents. This model suggests that senators may sometimes place their own values, knowledge, and ethics above the immediate desires of the people they represent.

The rationale behind this approach is grounded in the belief that elected officials are chosen not only to represent the views of their constituents but also to use their expertise and understanding of complex issues to make informed decisions that may benefit the public in the long run, even if those decisions have short-term unpopularity. This contrasts with voting as a delegate, where representatives primarily act to reflect the will of their constituents, or as a partisan, where they align closely with the interests of their political party. The politico model merges these approaches, but the trustee role distinctly emphasizes individual conviction as a significant factor influencing voting decisions.