CHARLESTON, S.C. -- John Kerry, the 2004 Democratic presidential nominee, gave Barack Obama a timely endorsement Thursday, snubbing Hillary Rodham Clinton as well as his own vice presidential running mate. Kerry came to South Carolina to embrace Obama, two weeks before the state's primary and with Obama needing a boost after Clinton's emotional victory over him in New Hampshire. Quoting a black American hero in endorsing the man who hopes to be the first black president, Kerry told a cheering crowd, "Martin Luther King said that the time is always right to do what is right." Now is the time,...