1. By essentially going AWOL (nobody knowing where he was, no phone contact, etc) in order to pursue contact with his (former?) mistress, he demonstrated that his private failures are affecting his ability to do his job.
2. His deceptions, evasions, bad decisions and immoral behavior, which by all accounts are out of character for him, demonstrate that his judgment has been impaired by (at least) his attraction to his mistress.
3. Most importantly, his top priority right now should be reconciliation with his wife and children, not attempting to salvage his political career. The fact that he’s a professing Christian makes this all the more true. Thankfully, his wife has indicated she’s willing to reconcile if he continues in repentance. He can demonstrate his commitment to that process by removing himself from his very stressful– and very public– job. That would also spare his family a good deal of the publicity they’re having to suffer through.

Sanford was right to call for President Clinton’s resignation in 1998, and to applaud Bob Livingston’s resignation as Speaker of the House designate the same year. He would do well to heed his own advice, resign for the sake of his reputation and his family, and let the political chips fall where they may.