he thinks he has a chance at being elected anything, and he thinks his third wife (the one he cheated on his second wife with) will help him.
"As he prepares for a Republican presidential primary run — he said Monday that he would formally declare his intentions on Wednesday — Mr. Gingrich is presenting himself as a family man who has embraced Catholicism and found God, with his wife as a kind of character witness. Depending on one’s point of view, she is a reminder of his complicated past, or his secret political weapon."
http://www.nytimes.com/2011/05/10/us/politics/10gingrich.html?hp