AN OPEN-MINDED individual, I am willing to support an adulterer for elective office. But my ability to look past marital infidelity depends on how much humiliation was heaped on the wife. The details matter.

And measuring their importance is hard. The unfaithful rarely conduct their affairs in a clean, compartmentalized matter.

For a wife, having a husband actually fall in love with a mistress must be the worst. When he chatters at length about his passion for the other woman, the pain can be excruciating. By this measure, South Carolina Gov. Mark Sanford’s crime is grave, exceeded only by that of former New York Mayor Rudolph Giuliani. Not only did Giuliani sing the praises of his lover, he compounded the cruelty by informing his wife of their impending divorce through a news conference.

In olden times, politicians were far more discreet. Franklin D. Roosevelt’s long relationship with Lucy Mercer hurt his wife, but Eleanor could act as first lady undogged by public scandal.

It can help matters when divorce is out of the question. The structure of a marriage stays intact, and the wife carves out her own life. Like Eleanor, Jackie Kennedy pursued her own interests as her husband John F. Kennedy philandered. Hillary Clinton followed the same path.

Love was not the driving force for Kennedy, or for Bill Clinton. It was almost certainly not the motivator for former North Carolina Sen. John Edwards. That also eases the wife’s burden.

Similarly, having a prostitute as the other woman should soften the wife’s mortification. New York Gov. Eliot Spitzer and Louisiana Sen. David Vitter both paid for sex. It was strictly business.

Learning that a husband sought out gay lovers should also lessen the wife’s sense of shame. The spouses of former New Jersey Gov. Jim McGreevey and former Idaho Sen. Larry Craig might be embarrassed to have the public think that they had no idea of their husbands’ proclivities. But their husbands’ extramarital relationships in no way reflected on their wives’ allure to hetero men.

The more hypocrisy involved, the more tawdry an affair becomes. During the presidential campaign, Edwards shamelessly portrayed himself as America’s most caring and committed husband while romping with a party girl. That Elizabeth was fighting cancer made his conduct more sickening.

Politicians who play the moralist, then stray, turn their marriages into laughingstocks. Nevada Sen. John Ensign was a long-time member of the Promise Keepers, dedicated to strengthening marriage. And Spitzer crusaded against prostitution.

Wives are not totally helpless in defending their dignity. Jenny Sanford’s refusal to play helpmate or tragic victim following her husband’s romp has made her a heroine to countless observers.

Silda Spitzer, Suzanne Craig, Hillary Clinton, Wendy Vitter and Elizabeth Edwards all appeared in their husbands’ contrition show. No one put a gun to their heads. If they did it to save their husbands’ political careers, that was their choice.

And some betrayed wives don’t deserve much sympathy at all. Thrice-married Newt Gingrich cheated on wife No. 2, with whom he had cheated on wife No. 1. How sorry can one feel for wife No. 2?

A political note: The recent high-profile Republican adulteries have effectively removed Gingrich from serious consideration as a presidential candidate. If Sanford and Ensign are disqualified, how could Gingrich contend?

Let’s end on a bright note. Many marriages survive and even thrive after infidelities come to light. Jackie was said to like Jack, despite his wandering. The same seems true of Hillary.

And those wives who want their politicos back might take comfort in the Stendhal line: “It’s not impossible to become bored in the presence of a mistress.”

Froma Harrop is a member of The Journal’s editorial board and a syndicated columnist.