I would assume his defense could argue a violation of the 14th amendment due process clause.
Procedural Due Process Civil
SECTION 1. All persons born or naturalized in the United States, and subject to the jurisdiction thereof, are citizens of the United States and the State wherein they reside. No State shall make or enforce any law which shall abridge the privileges or immunities of citizens of the United States;
nor shall any State deprive any person of life, liberty, or property, without due process of law; nor deny to any person within its jurisdiction the equal protection of the laws.
ANNOTATIONS
Generally
Due process requires that the procedures by which
laws are applied must be evenhanded,
so that individuals are not subjected to the arbitrary exercise of government power.
737 Exactly what procedures are needed to satisfy due process, however, will vary depending on the circumstances and subject matter involved.
738 A basic threshold issue respecting whether due process is satisfied is whether the government conduct being examined is a part of a criminal or civil proceeding.
739 The appropriate framework for assessing procedural rules in the field of criminal law is determining
whether the procedure is offensive to the concept of fundamental fairness.
(It is plainly obvious that fairness and evenhanded use of the law has not been evenly applied to political candidates. )