As a politician and as a judge, Declan Costello combined, in an almost unique way,  a deep and compassionate humanity , with courageous and unyielding principle.
He was eloquent and persuasive, without ever being demagogic.
More than anyone else, he inspired me to enter politics because he demonstrated, in the early 1960s, that political action could change society for the better.
 The Just Society policy document of 1964, with which his name will always be associated, was far more than an inspiring slogan. It was, in fact, the first of its kind in Irish politics up to that time, a very detailed policy programme produced by a party in opposition, objectively analysing society’s ills, and then prescribing detailed remedies.
 Its proposals   ranged from banking policy, to economic planning, to social capital investment, to health care and education.  It changed the political debate about the role of the state and, I believe, contributed indirectly to the introduction of free second level education in 1966. It also provided much of the policy ground work for the work of the 1973 to 1977 Government, in which Declan Costello served as Attorney General. In all this, Declan Costello showed himself to be a man who could work as a part of a team and inspire others without seeking limelight for himself.
As Attorney General, he was rigid in defending the legal system from politically correct or populist interference. The independence of the   office of Director of Public Prosecutions was a lasting and valuable legacy of his work. He also set up the Law Reform Commission, whose  valuable work is a fitting memorial to Declan Costello’s role  as a reforming politician .
As President of the High Court, a position to which it was my honour to propose him, he was courageous and rigorous in his judgements, as well painstaking and efficient in discharging the heavy  administrative burdens of that  busy office.
I extend  deep sympathy to his family.