David Goldman, AP
Republican presidential candidates, from left to right: Texas Gov. Rick Perry; former Pennsylvania Sen. Rick Santorum; former Massachusetts Gov. Mitt Romney; former House Speaker Newt Gingrich; and Rep. Ron Paul, R-Texas, pose for a photo at the start of the South Carolina Republican presidential candidate debate Monday, Jan. 16, 2012, in Myrtle Beach, S.C. (AP Photo/David Goldman)
It is far preferable for candidates to refrain from ugliness out of a sense of honor. The stakes are of course high — no less than arguably the most powerful position in the world — but never so high as to warrant a candidate compromising his or her character with ugly slanders.

As the postmortem on the GOP primary in South Carolina — a state with a reputation for dirty campaign tactics — continues, it turns a spotlight on one of the less savory sides of campaigning: the attack ad.

This season has certainly seen its share of negative advertising. From character attacks (such as those accusing Newt Gingrich of having "more baggage than the airlines" and Mitt Romney of being a heartless, French-speaking job-killer) to more issue-oriented spots (like those addressing Gingrich's moderate immigration stance or Romney's evolving opinions on social issues), this year's cascade of attack ads has ranged, as usual, from the factual to the silly.

Some negative ads serve a purpose. They are more issue-oriented and present more factual information than positive ads, which tend to focus mainly on squishy topics like the candidates' character and families. Underdog candidates, in particular, benefit from calling attention to an opponent's record and bringing up important policy issues as they make a case for why they would be a better choice.

But when negative ads cross from issue-oriented attacks to mean-spirited mudslinging, everyone suffers.

No candidate has been spared, but one analysis of political ads in South Carolina between Jan. 10-16 found that Gingrich was by far the biggest target, with 22 percent of all ads containing some anti-Gingrich material. (Just 12 percent of all ads placed Romney in the crosshairs, and 9 percent were aimed at Santorum.)

Gingrich complained loudly about attacks levied against him in Iowa, but days later joined his fellow candidates in the gutter with negative ads of his own, illustrating just how difficult it can be for one candidate not to participate in negative advertising when his opponents do.

This is precisely why talks between the respective campaigns of Sen. Scott Brown, R-Mass., and challenger Elizabeth Warren are so interesting. In an attempt to call off the attack dogs, the candidates have discussed such ideas as agreeing to donate 50 percent of the cost of a PAC ad to a charity of the other candidate's choice should an outside group air an ad in their favor.

This highlights, of course, the controversial role of super PACs in this election cycle. With no limit on the amount of money these "unaffiliated" organizations are able to spend promoting candidates or issues, they seem to have taken on the role of bad cop, allowing the candidate to stand back and play the good cop, even as they distance themselves from particularly vicious ads run in their behalf.

The super PAC advertising deluge raises important questions about definitions of free speech and campaign finance, but negative campaigning itself has been around as long as American democracy. The 1800 race between John Adams and Thomas Jefferson was one of the ugliest in history, along with the 1828 election that won Andrew Jackson the presidency.

The medium may have changed with the advent of television and the Internet, but the message of negative advertising has been part and parcel of politics since the beginning.

Yet in an encouraging new development, the new medium may also be part of the solution. Websites like factcheck.org, politifact.com and The Washington Post's Pinocchio Tracker make candidates and their super PACs accountable for half-truths, and have gained prominence in this election as the news media have begun citing them as often as the dirty ads they critique.

It is far preferable for candidates to refrain from ugliness out of a sense of honor. The stakes are of course high — no less than arguably the most powerful position in the world — but never so high as to warrant a candidate compromising his or her character with ugly slanders. We hope for a continued healthy debate, but one becoming of a civilized nation. Let us not lose our souls in the process of standing for our ideals.