I think an election year spotlights one thing: that there are people who are aware of their prejudices and people who aren't. I find myself seeing my candidate more favorably than the other candidate, even when they are doing the same thing. I think, "Well, my candidate wouldn't have done that if his opponent hadn't done it first." I am more outraged when the other party does slimy, outrageous things. I have a different name for it when my party does them. In fact, they don't usually seem slimy or outrageous at all.
Social psychology has consistently shown this. When football fans are shown tape of a game, they overwhelmingly notice the unfair calls against their team and rarely notice the equally unfair calls against the other team. When poor tippers are given an opportunity to comment on other poor tippers' habits, they justify their own behavior and condemn that of others.
It's indisputable that this is what happens during an election. How else to explain the way that sincere voters, who describe themselves as "objective," almost always shake out along party lines when they are asked to evaluate a debate or a campaign commercial? And voters who say they're undecided? Actually, we can predict with almost 100% certainty how they will actually vote just by looking at a scan of their brains. The primitive, emotional part of our brains know how we will vote before we do.
So, it seems that the best we can do is to be aware of our prejudices, our mental models, our distorted lenses and learn to take them out, look at them from different angles, evaluate their ultimate truthfulness as best we can and listen to people who differ from us. Especially that.