The answer is now only too clear, writes Andrew Marshall. Mr Gingrich, already known to be no champion of family values in his own life, was carrying on with someone else - a 33-year-old Congressional aide.
It began six years ago, when she was not that much older than Monica Lewinsky, she has admitted. Now, a torrent of sensitive and salacious sexual detail on Mr Gingrich is set to come spilling out, embarrassing the man who once thought that he, too, could be President. Mr Gingrich is facing retribution, and his party may join the firing squad.
His bitter divorce proceedings against Marianne, his second wife, are entertaining the nation much as Mr Clinton's saga of sexual incontinence did a year ago. Last week a judge ruled that Mr Gingrich must answer all the questions put to him by Marianne, which promises yet further sleaze for those who believe that politicians are constitutionally incapable of responsible behaviour.
Mr Gingrich filed for divorce in July, claiming that the marriage was "irrevocably broken". He has admitted his relationship with Callista Bisek, but denies that it is an affair. But she told the court in a deposition that though the relationship began in November 1993, when Mr Gingrich and his wife were legally separated, it continued after they were reconciled, and after Mr Gingrich was appointed to the august position of Speaker, which put him in line of succession to the presidency.
Ms Bisek, a tall blonde whose taste for sensible suits and pearls has been likened to Hillary Clinton's, works as an aide to the House Agriculture Committee and was reported as long ago as 1995 to be Mr Gingrich's "frequent breakfast companion".
According to her lawyers, he gave her a set of Callaway golf clubs and a pearl ring - "not even a really nice ring", one lawyer said, trying to erase the idea of an affair. "I don't think anybody's proud of the existence of the relationship," he said. "But it's a little different where you had a legal separation and something developed between two people."
Mr Gingrich told his wife he was seeing someone else last May, and that he wanted a divorce, but not that the affair had been going on for six years. That came out in an impromptu press conference. "I found out with the rest of the country," she told the Atlanta Journal-Constitution. "This is about a marriage. This is not about politics and another press conference. This is about my life."
Mr Gingrich was careful most of the time to distance himself from criticism of Mr Clinton's sexual behaviour during the impeachment process last year. "I've tried to make very clear that this is about the rule of law and it's about the law," he said then. "It's not about scandals in the gossipy sense or sexual behaviour in the gossipy sense. It's about whether or not the law has been violated."
He was already in a tricky spot. For a start, he was fined $300,000 for giving misleading information during an ethics investigation into his conduct. And his own family life is hardly a model of good behaviour. His mother's marriage to his father, "Big Newt", fell apart after three days. At 19 he married his maths teacher, Jacqueline. The couple were presented in campaign literature as the American Dream, and he criticised his opponent, Virginia Shapard, because her husband and children planned to stay in Georgia while she went to Congress: "When elected, Newt will keep his family together." Just over a year later, he filed for divorce.
He went to discuss the issue with Jacqueline while she was in hospital, recovering from a cancer operation. L H Carter, his campaign treasurer, told Mother Jones magazine that Newt said of Jacqueline: "She's not young enough or pretty enough to be the wife of the President. And besides, she has cancer."
During the 1974 campaign, several of his closest advisers realised he was having an affair, according to journalist David Osborne, He adds that a former aide approached Newt's car on one occasion with Gingrich's daughter, only to find that he was with a woman who had her head buried in his lap. He married Marianne in 1981.
In January, the Republicans are to celebrate the fifth anniversary of their arrival in Congress as the majority party in the House of Representatives. Mr Gingrich promised the party massive gains in last year's elections, but they lost seats. He resigned his post in the House and his seat shortly afterwards. His successor, Bob Livingston, lasted a few days until internecine warfare and revelations of his own sexual misadventures led him to resign. Now, Mr Gingrich himself may not be invited to the celebration.