Stealing this entirely from Atrios. But:

Has the Republican base become the fringe?

Yes.

This has been another edition of simple answers to simple questions.

Update: John Cole makes the point even more forcefully:

In fact, you could cite dozens of examples of these racist, divisive, dillusiuonal attacks on Barack Obama and conclude that they are just elements of the fringe and don’t represent mainstream Republicans.

Sooner or later though, you will have to acknowledge that this “fringe” is very widespread. You’ll have to come to grips, eventually, with the fact that this “fringe” has become the very definition of the your party.