One of the first guests Bill Moyers invited to Moyers & Company was moral psychologist Jonathan Haidt. His interview, which focused on differences in how conservatives and liberals think, is consistently one of the most-watched on BillMoyers.com.

This week’s interview with Green Party presidential and vice presidential candidates sparked a discussion in our editorial meeting about third parties, voting and the spoiler issue. Say, for example, that a voter reads the Green Party platform and feels like it represents their values and beliefs better than any other platform. Should they vote their heart — to send the signal that they support those policies — or should they vote for the party that comes closest to their beliefs and has the best chance of actually winning?

We wondered if there is a moral or “right” way to vote. So we emailed Jonathan Haidt, and asked him for his professional opinion.

Theresa Riley: Morally speaking, should a person vote for the candidate who represents their views most closely? Or should a voter game out the system and vote for the candidates who have the best chance of winning?

Jonathan Haidt: The ethics of voting depends on which view of voting you hold. Many people treat voting as a strategic game, a way in which people are trying to rationally pursue either their self-interest or their moral goals, or some combination. On this view it is always irrational as well as unethical to vote for a third-party candidate for president (unless someday there is one who might actually win). On this view, Democrats should be angry at Ralph Nader and at everyone who voted for him. Together they changed the world in profound and irreversible ways.

But from my perspective as a social psychologist, I think voting is more like religion than it is like shopping or chess. Some sociologists have described the “American civil religion,” with its sacred texts (the Declaration of Independence, the Constitution), sacred cities (Jamestown, Valley Forge, Gettysburg…), and high priest (the president). Elections are the main religious ritual of democracy, and from this perspective people should vote their conscience.

Riley: On Tuesday, Virgil Goode, Jr., the right leaning Constitution Party candidate for president got on the ballot in Virginia. Republicans had been trying to keep him off the ballot because they fear that he may take votes away from Romney/Ryan. Are they correct to worry about that? Are conservatives or liberals more likely to vote their hearts?

Haidt: Yes, the Republicans are right to worry. Nowadays the American electorate is very closely divided, and many races are very close, particularly in swing states such as Virginia. I think Goode deserves the anger of Republicans as much as Nader deserves the anger of Democrats. Goode’s candidacy could very well change the outcome of the presidential election.

I do not know that either side is more likely to vote their hearts. Peoples’ votes are strongly influenced by their emotions, including anger, fear and hope. Whichever side is more emotional in a given election cycle will seem to be voting more with its heart.

Riley: In a 2011 Gallup poll, 52 percent of Americans said they don’t think the two parties are doing a good job and that a third party is necessary. But earlier this summer, when presented with a list of candidates running for president, only about 5 percent said they would vote for a third-party candidate. Why do you think that is?

Haidt: I think the two parties are doing a good job only at what they are designed to do: beat the other party. I think they are doing a terrible job of addressing the nation’s problems. (See Mickey Edwards’ new book, The Parties vs. The People for more on how this came to be). It is perfectly consistent for Americans like me to dislike both parties and long for a third party, while refusing to throw away their vote in the current election on a candidate who can only be a spoiler.

Jonathan Haidt is the author of The Righteous Mind.