Justice Ní Raifeartaigh’s decision for the High Court focused on the importance of the separation of powers as codified in the Irish Constitution and the importance of parliamentary privilege in a democratic society.

Referring to Irish case law and jurisprudence from European courts and other jurisdictions, the Judge said it was clear that the courts, in policing the boundary between their functions and those of  parliament, have been careful to ensure that legislation does not directly or indirectly interfere with core elements of the administration of justice, such as weighing evidence and reaching conclusions upon the law and evidence. The courts have also been careful to avoid stepping outside of the boundaries of their own constitutional role into a role exclusively reserved for parliament.  O’Brien had relied heavily on the case of Buckley & Ors. v The Attorney General & Anor, a leading authority on the principle that Parliament may not enact legislation which directly interferes with the function of administering justice entrusted to the courts under the Constitution. However, the Judge distinguished this from the present case on the basis that, in Buckley, Parliament had sought to direct the courts on how to determine the proceedings which was “interference of a most direct kind with the administration of justice” whereas in the present case the members released information sought to be protected by the courts into the public domain, thereby rendering the judicial proceedings moot.

Nevertheless the Judge stated that the use of parliamentary speech to render a confidentiality action before the court moot was itself a significant action which had had a substantial effect on the judicial proceedings and that the “issue remains as to whether there was an ‘interference’ with the administration of justice and whether the courts have jurisdiction to entertain proceedings concerning the utterances.” She said that this raised the question of justiciability and went on to consider the parliamentary immunities and privileges contained in Article 15, sections 12 and 13 of the Constitution to establish whether the Court had any power over the regulation of such speech.

She referred to the Irish Supreme Court decision, Attorney General v Hamilton [1993] 3 IR 227 (“Hamilton No. 2”) on the scope of the privileges and immunities in Article 15 of the Irish Constitution. In that case, Geoghegan J. engaged in a detailed review of the origin and purpose of Article 15, sections 12 and 13 and compared them with the American Bill of Rights and several common law authorities from England, the U.S. and Australia. Geoghegan also noted that section 3 of Article 15 states that members ‘shall not, in respect of any utterance in either House, be amenable to any court or any authority other than the House itself.’ Justice Ní Raifeartaigh also quoted Hamiltion No. 2 to the effect that a House member not only cannot be disciplined by the court for his utterances, but also cannot be forced to explain them to the court. Justice Ní Raifeartaigh went on to reference more cases in which it was held that it would be inappropriate for the court to intervene with parliamentary speech, save in  exceptional circumstances, which she said were restricted and did not apply in the present case.

The Judge, again citing Hamilton No. 2 that “the privilege and non-amenability is absolute and intended by the Constitution to be absolute in the sense even that it cannot be sacrificed to protect other constitutional rights“, stated that neither constitutional rights nor even the administration of justice outweigh parliamentary privileges. She also referred to Denham J.’s opinion in Attorney General v. Hamilton [1993] 2 I.R. 250  (“Hamilton No. 1”) where she considered the protection of what falls under parliamentary privilege to be very broad because parliamentary privilege is recognized as being an important element of the democratic process. The Judge also reiterated that while the exercise of privilege would have  consequences and some of those severe, these actions still fell to be decided and administrated upon by the House.

In Justice Ní Raifeartaigh’s concluding remarks, she stated that Article 15, s. 12 is not confined to documents as argued by O’Brien. She also dismissed his attempt to bypass parliamentary privilege by taking action against the Clerk to Parliament, the Committee on Procedure and Privileges and the Attorney General, rather than suing the members of the House who had made the utterances. She said the use of procedural loopholes did not detract from the immunity or privilege that existed regarding the matter. Similarly, the fact that declaratory relief was being sought made no difference and it would not be proper for the Court to grant relief. “The fact that declaratory relief was sought seems to me to be merely a device to try to soften the appearance of what in fact is being asked of the Court; the Court is being asked to take parliamentary utterances and subject them to judicial determination”, she said. Even giving the Court the ability to discern which parliamentary speech is considered legitimate versus illegitimate, would have a chilling effect on freedom of expression, she added.

The remaining limbs of O’Brien’s case concerned the actions of the Committee on Procedure and Privileges, which were found non-justiciable for similar reasons to those stated above.

On October 10, 2017 O’Brien was granted leave to appeal directly to the Supreme Court.