Tonight, Bill Clinton, whom I used to work for as chief White House speechwriter, will give a major address to the Democratic convention. Startlingly, that same sentence could have been written in 1988, 1992, 1996, 2000, 2004 and 2008. Think of Springsteen at the Meadowlands. Even if you don't really like the music, you must admire the longevity. This Clinton convention speech is more important than most—certainly, it’s more riveting. It’s topsy-turvy for a former president to place in nomination a current chief executive.