The article does not state that the former mayor is a Republican, but I will take your word for it.
However, as of today, the GOP is the minority party and if Republicans wish to remain the minority party, all they need to do is defend their elected officials who sent out racist jokes via email.
The mayor is a Republican.
http://sitfu.blogspot.com/2009/02/los-alamito-mayor-dean-gros-republican.html