BOSTON - At conventions devoted to electing next presidents, there's always the question of what to do with ex-presidents, not to mention those who ran and lost. The answer: as little as possible, and get it over with. Democrats go into their convention Monday needing to accommodate one big brassy winner, Bill Clinton (news - web sites); the towering Kennedy legacy, and a succession of people who have accomplished much but don't wear the magic aura of success. A few of them, in fact, represent crushing defeat. Clinton was allotted a prime time speech Monday night, a hail to the...