Final answer:
National party conventions have become less important due to the decisive nature of primary elections, their transformation into scripted media events, and reduced media coverage. They still serve as platforms for adopting party platforms and showcasing future party leaders.
Step-by-step explanation:
National party conventions have seen a decrease in importance compared to past decades due to a number of factors. Firstly, the rise of the primary elections has ultimately led to conventions becoming a formality where the nominee has already been largely decided by the public and party insiders play a lesser role. This has reduced the suspense and unpredictability that once characterized these events. Secondly, the conventions have evolved into highly orchestrated and sanitized media spectacles, with prescreened speeches and controlled protest areas, which diminish their authenticity as platforms for open political discourse. Furthermore, the reduction in media coverage implies that these events no longer captivate the national audience as they once did. Despite these changes, conventions still serve critical functions, such as the formal adoption of the party platform, the beginning of the official presidential campaign, and showcasing emerging party leaders. For example, Barack Obama's notable speech at the 2004 Democratic National Convention heightened his national profile significantly.