Words have meaning.  If a person uses a racial slur and an otherwise inexplicable adverse personnel action occurs, then we may have pretty good circumstantial evidence of racial discrimintion.  So, what is a racial slur?  One candidate for the Texas Senate seat, Chris Mapp, said "wetbacks" should be shot.  Mr. Mapp hails from Port O’Connor, deep in South Texas.  He insists that word is a "normal" term in South Texas.  See San Antonio Express News report.  He used the term when he met with the editorial board of the Dallas Morning News.  He later defended his use of the term when he met with the San Antonio Express News editorial board.  He said the term is as normal as "breathing air" in South Texas. 

I have spent much of my life in South Texas and can say that sometimes, "wetback" is normal.  Ii is a phrase often used by persons with little or no respect for illegal immigrants.  I once served as commander of a National Guard company in Robstown, Texas for three years.  Co. D, 2/141 was perhaps 98% Hispanic.  I am sure I never heard the "wetback" term during my tenure.  So, sure, his use of the term in certain circumstances would be good evidence of racial discrimination.  If there was an otherwise unexplained personnel action toward a Hispanic employee, Mr. Mapp’s use of the term "wetback" would be key evidence.  A jury makes the ultimate decision regarding what is or is not a racial slur.  But, I would bet my money that Mr. Mapp would lose in front of most South Texas juries.