Typical american "left" and "right" skewed over time to the right so much, their "left" is still in the right. The same happened in Canada, not as much though, but the UK is even worse than the US, the idea is to show off the main 3'rd parties in the US. This wouldn't work on a left-and-right line, because then Saddam and Gandhi would line up and the democrats would seem more extreme than hitler. Where the parties are on the map is based on the candidates in the 2004 election.
You can see where you stand on the same grid here [link]
This is supposed to be like an educational poster, like [link]