<p>CHARLESTON, W.Va. (Reuters) - Democrat John Kerry, promising a "great debate," declared victory in the Democratic presidential race on Tuesday and formally opened the general election campaign with an assault on President Bush's credibility.</p>
<p>With a win in Illinois, Kerry acknowledged he had enough delegates to July's nominating convention to claim the right to challenge Bush in November -- a formality given that most delegate counters put him over the top last week.</p>