Lexington mused over the fondness that Americans have developed for monarchy (a reference to the fact that if Hillary wins in 2008 then there will have been 24 years of uninterrupted rule by a Clinton or Bush from January 1989 to January 2013 and possible another 4 years until January 2017), but glossed over the fact that it is America's own political system that has given the White House its "air of royalty". The biggest difference between parliamentary systems and American-style presidential systems is that the former are based around robust political parties that are the proving grounds for testing, developing and supporting political leadership. America's system, with its comparatively weak and diffuse party structure, is increasingly a "celebrity" based model, in which each presidential candidate has to create his or her own personal political party for fund-raising, advisers, etc.
In such a personality-driven system, a candidate's family members already have the advantage of name recognition that helps them raise money if they choose to run. They can also rely on the coterie of friends and advisers to the family that has been built up by previous campaigns. George Bush is the classic example of this. In 2000 more attention was paid to his inheritance of the Bush family mantle than on his meagre record as governor of Texas. Today, the celebrity factor dominates the current primary campaigns, with the media focusing on personalities and paying little attention to substantive policy issues.
Here is the article that "Lexington" refers to http://www.economist.com/opinion/displaystory.cfm?story_id=9149798