It bothers me that people think that only an aristocracy should be allowed to vote.
1) It is not established that IQ predicts which side of the margin your vote falls on. It is just as likely to select for high IQ as for low, without data to base that distinction on.
2) Voting rights are not denied to some based on IQ for a very good reason. You want a constitutional amendment to clarify this point then I wish you luck.
3) Those belonging to your target groups ("right wing, red neck, racist, fundamentalist, cretins as well as the left wing variety.") are ruled by our democracy. They have as much right as anyone to exercise their small amount of control over the government.