<p>WASHINGTON - What was supposed to be a sporting, four-city competition for the 2004 Democratic National Convention has been transformed into a power struggle between two of the country's leading political families: the Kennedys and the Clintons.</p>
<p>Senator Edward M. Kennedy of Massachusetts is spearheading Boston's drive to host the party gathering, telling each of the Democrats' potential presidential candidates that, as he passes age 70, he wants to finally bring the convention to his home state.</p>