It was a busy day for the Supreme Court, yesterday.  The high court decided a second employment case regarding retaliation cases.   Congress amended Title VII in 1991 to add many new facets.  It also added that to show discrimination, a plaintiff needed to show that discrimination was a "motivating factor."  Did that change also apply to retaliation claims?  That question has been litigated ever since the amendments first went into effect.  In Univ. of Texas Southwestern Medical Center v. Nassar, No. 12-484 (6/24/13), the Supreme Court ruled in another 5-4 decision that the appropriate standard for Title VII retaliation claims is "but for" analysis.  That is, would the employer have taken the adverse employment action "but for" the retaliatory motive?  

"But for" is generally considered a more rigorous standard of proof.  But, really, this decision may make no difference to most claimants.  The difference between "but for" and "motivating factor" is hazy.  It is a subjective analysis and may make little difference to most juries.   See Supreme Court decision here.  See Scotus blog for an excellent discussion of the competing theories of proof.