The ways that states hold party primaries may have profound implications for civility in all elected offices. The basic problem is that only the most committed voters on each side vote in primaries — usually less than 10% of the eligible electorate. Given how many elected positions are "safe" — meaning that one party is virtually guaranteed to win, this means that the primary is, essentially, the whole election. When elections are decided by primary voters, then less civil candidates have an advantage over more civil candidates. 

Some of the issues/changes that might influene civility include:

1) Having open primaries, in which anyone can vote, as opposed to closed primaries, in which only people who have previously registered as being a Democrat or Republican, can vote in thier party's primary.
—This essay by Perry Stein in The New Republic quotes Jeffrey Skelly at the University of Virginia's center for politics: "the effect of open primaries, especially in competitive races, has been to strengthen the state’s political independents and dilute the influence of partisan ideologues. It’s no accident that states with open primaries often nominate more temperate politicians than those with closed primaries." [added by haidt, 2/12]

–See this essay, by Mickey Edwards, recommends open primaries

2) Alternative voting methods: Our current system of voting for a single candidate has so many problems, most notably that when there are 3 or more candidates, any that are similar to each other split the vote so that the 3rd candidate wins, even though he would have lost in a straight-up election between him and either of the two similar candidates. There are three major contenders for solving this problem and getting us closer to a voting system that picks the candidate that is truly the one most favored by voters.

 A)Instant Runoff Voting: people rank their several top choices, so candidates have an incentive to appeal more broadly, so that they are the second or third choice of many voters. However, IRV is complicated and hard to explain to voters, and some argue that IRV can produce odd results that can sometimes favor extremists.

B) Approval voting. Voters simply vote for ALL the candidates they approve of, and the winner is the one who gets the most votes. This solves most of the problems of standard voting and has the great advantage of supreme simplicity. It is similar to the way a group of friends might choose a restaurant to go to, after they've nominated a few choices. Here is an argument that approval voting is better than IRV.

C) Range or Score voting. This is just slightly more complex than approval voting. Each voter gives a score (0-9) to each candidate, and the winner is the one who gets the highest point total. This is also pretty simple and familiar: it's basically how gymnasts are scored in the olympics.

–See a great list of reforms offered by Mickey Edwards  (former Republican congressman).

This page is edited by Jon Haidt