Politics is the art of the possible.
So said Otto Von Bismarck in 1867 and he was surely right. One of the challenges for an idealist is that compromise is a necessary and appropriate component of the political process. It happens within parties and it happens within legislative bodies. In both cases compromise is necessary because all decisions in those settings affect a number of people who are in a variety of life situations and hold varying goals for themselves and their communities and good decisions cannot be made without addressing the concerns and perspectives of those various parties. Some dislike this reality – and certainly some use it as an excuse to abandon all principle, but the ability to recognize when and how compromise is appropriate is an important skill for any good legislator.
Obviously the ability to analyze and communicate with colleagues and constituents is a critical prerequisite for a legislator to be an effective negotiator. The real challenge once the analysis and communication abilities are in place is knowing how to balance the ability to negotiate with the understanding of what values or positions are non-negotiable. A legislator should be a good negotiator, but they should not be a chameleon or even a contortionist.
Part of their negotiation must be that there is a core which is immutable – one that they have communicated to constituents. The constituents should be able to depend upon this core of principle to predict how their legislator will represent them and the legislator should be able to articulate how their actions during negotiations conform to those core principles. Once the core of principles has evaporated in the face of their legislative record constituents should be quick to replace their legislator – and a legislator should expect no less from their constituents.