Poli-Sci Perspective is a weekly Wonkblog feature in which Georgetown University's Dan Hopkins and George Washington University's Danny Hayes and John Sides offer an empirical perspective on the issues dominating Washington. In this edition, Hayes looks at research summing up whether and when politicians can survive scandals. For past posts in the series, head here.

When former South Carolina governor Mark Sanford last week won the GOP nomination for an open congressional seat, he became the latest politician to find electoral success after seeing his career tarnished by a scandal.

But we shouldn’t be surprised. If Sanford, who in 2009 admitted to an extramarital affair, wins an open House seat May 7, he will join a long line of political survivors. Scandals make it harder for office holders to get reelected, but they’re usually not fatal. That’s according to new research by political scientist Scott Basinger.

Like everyone, political scientists have had a long-running interest in scandals. In the wake of the house banking scandal in the early 1990s, for instance, several pieces of research suggested that incumbents who had written bad checks were more likely to retire and were more likely to face strong challengers than representatives who were not implicated. Scandals may have other effects, tarnishing voters’ views of candidates’ character, although a more recent finding suggests that the consequences of sex scandals might have a short shelf life.

But little research has considered the effect of multiple scandals over a lengthy time period. That’s where Basinger’s study comes in.

He first compiled a database of every scandal involving a U.S. House member since 1973, the golden age of American political wrongdoing. In the post-Watergate era, 237 representatives were implicated in various forms of malfeasance.

Between 1973 and 2010, Democrats accounted for 63 percent of scandals, Republicans the remaining 37 percent. Does that mean that we have one party of angels (Republicans) and one party of devils (Democrats)? Probably not. The divide is due at least in part to the fact that Democrats held more House seats over the four decades of the study.

Basinger then categorized the scandals into four types: financial, corruption, sex and political. (There’s also a residual category for offenses like illegal drug use, trespassing and DWI.)

Thirty-seven percent were financial scandals, by far the most common. Corruption, sex and political scandals each accounted for less than 20 percent. For all the attention to the Bill Clintons, Chris Lees and Anthony Weiners of the world, it might seem surprising that sex scandals aren’t the most frequent type. But it looks like Biggie was right: Mo money, mo problems.

So how does scandal affect incumbents’ political fortunes? Basinger finds scandal-tainted incumbents are more likely to retire than other members. They also are more likely to lose in primary elections, as fellow party rivals swoop in to take advantage of an incumbent’s difficulties.

About 73 percent of scandal-tainted incumbents make it to the general election. By comparison, 91 percent of scandal-free representatives do. Bad behavior hurts, although it is nothing like a political death sentence.

In the general election, a scandal costs incumbents, on average, five percentage points at the ballot box. There are two things to keep in mind, however. First, the incumbents who retire or lose in primaries are probably the most vulnerable. That means these effects – based only on incumbents who manage to reach the general election – are probably underestimating the real cost of a scandal.

Second, the five-percentage-point average obscures variation in the effects of different types of scandals. Corruption scandals – those involving allegations of bribery, obstruction of justice, or, say, questionable Caribbean vacations – do the most damage, costing incumbents almost eight percentage points. Financial and sex scandals reduce incumbents’ vote shares by five points. But political scandals – involving campaign finance or disclosure misdeeds – don’t appear to matter at all. It may be that voters simply care less when incumbents break campaign finance rules, and it may also be easier for politicians to explain away such violations as the result of complicated campaign finance regulations.

While scandal-tainted incumbents have to work harder to win reelection, 81 percent do. All considered –after resignation, retirement, primary losses and general election losses – Basinger’s data show that 60 percent of scandal-tainted incumbents ultimately find themselves back in Congress.

Not all scandals are created equal, of course. They vary in scope and importance, as well as the amount of attention they receive. A widely publicized scandal about clear financial or criminal wrongdoing likely will be more difficult for an incumbent to overcome than an obscure technical violation involving Federal Election Commission paperwork.

But the overall patterns suggest that American voters are a fairly forgiving, or at least forgetful, people.

If Sanford wins next month, he will be just one of many elected officials to secure a seat in Congress after a scandal. But he will certainly be the first to have taken the “Appalachian Trail” to get there.