The Democrats and Republicans share a fundamental goal for their upcoming national conventions: to produce scripted television shows that will boost their candidates' prospects in the general election without showcasing any intra-party squabbling. Under that scenario, convention delegates seem to have nothing to do but cheer Barack Obama and John McCain, whose nominations were virtually assured before the conventions began. If the important decisions are made before the conventions begin, ask some politicians, political scientists and critics in the media, why bother to hold them? Convention supporters argue that the gatherings are needed in case a nomination isn't settled beforehand. The conventions also make decisions about party rules that can affect which candidates get nominated. And conventions are the one time every four years when the parties become truly national organizations, with delegates and activists from around the country mingling face-to-face.