Definition of empty claim:
(n) :
A podium or chair left empty to highlight the absence of someone from a debate.
(n) :
A position held by someone who is absent or otherwise ineffectual.
(n) :
(psychotherapy) A chair which is used to personify the client's object of conflict
(v) :
(transitive, debating) To draw attention to (a person who is absent from a debate) by providing an empty podium or chair which they would have occupied.