Discrimination.
There is no administrative exhaustion requirement for S1981 actions.
The statute of limitations began to run with the adverse personell actions, not the written warning, as the adverse etiology had yet to crystallize.
A name-clearing hearing is not constitutionally required where the speech is not broadcast to a larger public, there is no nexus with the end of employment, and the employee did not request one.
http://media.ca1.uscourts.gov/pdf.opinions/15-1667P-01A.pdf
Since 2011. An occasional commonplacing of the U.S. Circuit Courts of Appeal.
Neither an authoritative statement of the law nor legal advice. Quick work.