Lead With Values and Vision

Programs are a major problem for attempts at unity. As soon as a policy is made specific, the differences must be addressed. Progressives tend to talk about policies and programs. But policy details are not what most Americans want to know about. Most Americans want to know what you stand for, whether your values are their values, what your principles are, what direction you want to take the country in. In public discourse, values trump policies, principles trump policies, policy directions trump specific programs. I believe that values, principles, and policy directions are exactly the things that can unite progressives, if they are crafted properly. The reason that they can unite us is that they stand conceptually above all the things that divide us.
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Having those shared values, largely unconscious and unspoken, is not good enough. They have to be out in the open, named, said, discussed, publicized, and made part of everyday public discourse. If they go unspoken, while conservative values dominate public discourse, then those values can be lost–swept out of our brains by the conservative communication juggernaut.
Don't just read about these values here and nod. Get out and say them out loud. Discuss them wherever you can. Volunteer for campaigns that give you a chance to discuss these values loud and clear and out in public.

– George Lakoff, The All New Don't Think of an Elephant!, “What Unites Progressives”

Put another way, values, principles, and policy directions are how you build a movement. Policies are how you implement the vision once the movement has critical mass. When building a movement you don't worry too much about folks with a drastically different world view; you're just trying to find all of your friends. But when it comes to policy, it's important to work with folks from “the other side.” A policy which is supported by many members of some movements has a better chance of surviving than a policy which is supported by all and only one team.