Carol Moseley Braun, who ended her presidential campaign this week, is frequently and accurately described as the only African-American woman ever to serve in the United States Senate. But, assiduous newsreader though I am, I have never seen her identified by the following descriptor, which in addition to being equally accurate is vastly more remarkable: Carol Moseley Braun is the only African-American Democrat ever to serve in the United States Senate. Isn't that really astonishing? A political party that for the past seventy years has claimed the allegiance of as many as ninety per cent of the black voters of...