Personal Scandal, Political Success

With his victory Tuesday in a special election for Congress, Mark Sanford provided the latest evidence that, contrary to F. Scott Fitzgerald's famous dictum, second acts are possible in American life.

That seems especially true in U.S. politics, where voters have proven themselves willing to forgive and, if not forget, at least re-elect politicians who have strayed from the straight and narrow.

Once, a mere photo with a woman who wasn't a candidate's wife could destroy a race—as happened to former Sen. Gary Hart in the 1988 presidential election. A...