Independents4Change TD Joan Collins has lost her challenge to the Minister for Finance's decision to issue €31bn in promissory notes to Anglo Irish Bank and other financial institutions.
The notes were effectively IOU notes from the State allowing Anglo Irish Bank and other financial institutions to get emergency funding from the Central Bank in 2010.
Ms Collins argued that the Minister for Finance did not have the power to allocate an unlimited sum of public money.
She appealed the High Court's rejection of her challenge.
The core issue in the case was whether or not the Minister for Finance had the power to allocate unlimited sums of public money without the funds being quantified and considered in advance by the Oireachtas.
Ms Collins' legal team described this as an enormous case and argued the constitution did not permit the allocation of unlimited monies.
The State argued the minister had the power to issue the €31bn in promissory notes to Anglo Irish Bank, the Educational Building Society and Irish Nationwide Building society under 2008 legislation enacted by the Oireachtas to prevent a banking collapse.
In the judgment, which was delivered by Chief Justice Susan Denham, said the legislation was "undoubtedly exceptional".
But she said it was a permissible constitutional response to an exceptional situation.
However, Ms Justice Denham said it could not be considered as a template for broader ministerial power on other occasions.
She said it was unlikely the Oireachtas would concede such wide ranging power in other less pressing circumstances.
But she said if it did, and a minister or other body was permitted to provide unlimited financial support, without limitation in time to any commercial entity, then it would not follow from this case that such would be constitutionally permissible.
The ruling also found that the fact that no financial cap was placed on the financial support capable of being provided, might be imprudent.
Or she said it might be an entirely prudent, though necessary and awesome response to an exceptional situation.
In either case the Chief Justice said it is a decision made by the organ empowered by the Constitution to do so.
She said the Oireachtas was free to decide to impose limits on the extent to which the State may borrow or spend but that decision is one consigned by the Constitution to the legislative branch and not the judicial branch of government.
In the ruling, the court found the limits placed on the exercise of ministerial power under the 2008 act did not include a financial cap, beyond which the financial support could not extend.
But it found the Constitution did not require such a limit.
The court found that the Constitution requires that the functions it confers on the organs of State must be exercised by the appropriate organ and no one else, in the manner set out in the Constitution and in no other way.
In the ruling, the Chief Justice said it was true that in this case the potential exposure was enormous.
The amount was vast and the impact on the State's finances significant.
She said the legislation was exceptional but that did not make it unconstitutional.
She said it was designed and tailored to meet an exceptional situation - addressing an extraordinary risk to the State's economy which could be said to represent a systemic economic danger.
She said it was a feature of financial crises that matters move very quickly and speed is often of the essence.
If it was accepted that it was appropriate to make provision for a swift response to a financial crisis in a credit institution, then there can be no quarrel with the fact that the minister for finance was the body designated to make that decision.
She said if this was permissible, then it was difficult to understand how the absence of a financial limit could render the provision unconstitutional.
The Chief Justice said the court had no function in considering the wisdom of decisions taken by other branches of government, only a limited capacity to review them in judicial review proceedings.
She said it was the court's function to ensure that the constitutional organ which has the responsibility to make such decisions whether they be wise or foolish, trivial or far reaching, was allowed to do so within the limits imposed by the Constitution.
She said the momentous nature of the decisions which have been made in relation to the crisis which the Irish economy experienced in recent years, including those made in this case, highlighted the importance of each organ of government respecting the field of operation of the other branches and performing its own functions conscientiously and carefully.