Pure and simple all the policy ideas in the world don't matter if I don't trust you to do what you say, don't think you have the leadership abilities to do what you plan, or think that you have the backbone to follow through when you are challenged. I know that many people here will choose their candidate based purely on positions, but I don't think that is true of most of the electorate nor do I think it should be.
We are electing candidates based on what we think they will do in the future, and how they will affect the future of our nation. Past performance is usually a good indicator of how they will perform in the future, but so is our own judgement of what they really plan to do and why they plan to do it. We also need to be confident that they have the intelligence and judgement to make good decisions about problems that have yet to arise. For all of these reasons we need to choose a candidate who has both integrity and ability.