Here is my US external perception of the american political landscape. First thing: In my country political parties are strictly ideological, there is a communist party, socialist party, social democrat party, social liberal party, liberal party, libertarian party, conservatives party, populist party, muslim party, far right party. Since you need a majority, we tend to see a division down the middle, with the social liberal party switching side regularly. (Liberal used in the classical EU sense)
In the US the two major parties are not strictly ideological, but more act as an election block. Since there are fringes in both parties, the left tries to label all republicans white supremacist and the right tries to label all dems as communists. The resent shift to the left in the dems have caused the libertarian and classical liberal minded voters to abandon the dems. Only a minority of them have gone to the republicans. If you agree with Martin Luther King or John F Kennedy your positions are now best represented by the republicans.
