Eamon Ryan claimed his exclusion was interfering with the democratic process
The Green Party has lost its bid to be included in the second general election leaders' debate on RTÉ.
The national broadcaster had insisted its decision to exclude Eamon Ryan from tonight's debates was "fair, transparent and independent".
Ms Justice Marie Baker said the criteria used by the broadcaster was not unfair or irrational or disproportionate.
The Green Party leader was not asked to participate because his party did not meet the criteria, which requires it to have at least three outgoing TDs.
This action was brought by Tom Kivlehan, a trustee for the Green Party, who challenged the rules applied by RTÉ when compiling their invite list.
Last week, lawyers for RTÉ told the High Court it applied objective, impartial and transparent criteria for inclusion.
Aside from Mr Ryan's exclusion being "unfair", he also claimed it was in breach of RTÉ's legal obligations and accused the broadcaster of interfering with the democratic process - a process that is protected under the Irish Constitution.
The court heard about a complaint sent by Mr Ryan to the Broadcasting Authority of Ireland (BAI).
In it, he claimed the exclusion suggested to the public that the Green Party is not a "significant player" - a message that will be detrimental to their election campaign, he said.
The BAI said it could not intervene until after the debate is broadcast, which is why Mr Kivlehan initiated this judicial review.
The first of the two debates will be broadcast on RTÉ television tonight from 9.35pm.
Mr Ryan says he is disappointed at the outcome, and that the Green agenda needs to be heard.