Dennis Kucinich and Mike Gravel are depicted on the extreme left in an American context, they would simply be mainstream social democrats within the wider political landscape of Europe. Similarly, Hillary Clinton is popularly perceived as a leftist in the United States while in any other western democracy her record is that of a moderate conservative.and plots the candidates like so on the graph:
( Plot of positions of main candidate )
It's telling how close together they all are, and I concur completely with their analysis on it being linked to the electoral system. It also shows why I keep getting Kucinich on all those "who should you vote for" things that are kicking around.
Of course, the US media is even more biased than in the UK, and is almost completely beholden to corporate/advertiser interests; at least in the UK the press is following market positions at the same time as trying to affect that market (if anyone really thinks Murdoch backed Blair for political reasons then they really weren't paying attention). The result of this is that candidates coalesce around a media friendly center, but the media/mainstream is so far to the top/right that anyone else looks extreme. Ah well.
Land of the free, home of the brave. As long as the corporations are happy with you.