Galway West TD Éamon Ó Cuív has said he is to remain a member of the Fianna Fáil party.
Speaking to the media outside Leinster House this evening, the party's former deputy leader said he was not quitting, despite his continued opposition to the EU fiscal treaty.
Deputy Ó Cuív, grandson of Fianna Fáil founder Eamon de Valera, said attaining the leadership of the party was not his aim, but he believed with "all his heart and mind" that the EU fiscal treaty referendum is a "mistake".
"I believe that the only way to make a sustained impact in politics over a long period is as a member of a political party, particularly a party such as Fianna Fáil with a large membership around the country," he said.
"This has been one of the most difficult decisions of my career.
"After careful consideration of the situation, I believe that the best contribution I can make is as a member of Fianna Fáil."
The 61-year-old said he had been heavily influenced by the advice of supporters, who urged him to work for change from within Fianna Fáil.
He dismissed speculation that had any intention to join another political party, and said he would not be making any further media comment in relation to the upcoming referendum on the EU fiscal treaty.
“There has been some speculation in recent times as to whether I would ever join another party. I would like to make it clear once and for all that I see no other party other than Fianna Fáil that represents my political views,” he said.
Deputy Ó Cuív said he had been urged by supporters in his Connacht constituency and from around the country to remain.
“I will therefore continue to work from within to restore the party to its original ethos of representing all classes and creeds in Ireland bound by the common purpose of working for the good of all Irish people as opposed to any sectional interest,” he said.
Deputy Ó Cuív said he would be a powerless force if he left the party to stand as an independent TD.
He called on the electorate to study the long and short-term impacts of the treaty before voting.
Party whip Seán Ó Fearghaíl wrote to the TD setting out the party’s response to his refusal to support the treaty and Yes side in the May 31 referendum.
In the correspondence the whip said that there was no way the party could allow a senior member to advocate against a policy over a long period of time and that all TDs had stood in the 2011 election under the same banner.
“I think we need to put this controversy aside, respect the party’s rules and traditions and move on to the wider and more important challenge of showing how Fianna Fáil offers a credible alternative to this government,” Mr O Fearghaíl said.
“You have a very valuable role to play in this process.”
Deputy Ó Cuív was forced to give up his role as deputy leader in February when the row over the fiscal treaty first broke. He said then that the party should have taken its time to consider its pro-Europe stance and that Ireland should seek a debt write-down.
Deputy Ó Cuív, who was raised and educated in south Dublin but always represented the Connacht constituency, ran unsuccessfully for the Fianna Fáil leadership after former taoiseach Brian Cowen stepped down in 2011.
Deputy Ó Fearghaíl said he welcomed Deputy Ó Cuív's decision to clarify his stance and to help in the renewal of the party.
“The Fianna Fáil party is clear in its view that Ireland must remain outward looking and a strong voice at the heart of Europe,” Deputy Ó Fearghaíl said.
“We are also of the view that having called for a more robust financial response from Europe to help those countries experiencing difficulty, we should now move quickly to ensure we have access to this support if we need it.
“For these reasons, we believe that the Stability Treaty is an important first step on the road to recovery. We will be campaigning in favour of the treaty and will be talking to members and supporters across the country asking them to vote ’Yes’ on May 31 in the best interests of the Irish people.”