The Tánaiste has been accused of "throwing Dr Maitiú Ó Tuathail under the bus and then reversing over him".
Taking Leaders' Questions in the Dáil, Leo Varadkar denied the charge from Sinn Féin's Pearse Doherty, saying that he had taken "sole responsibility" for leaking the document to Dr Ó Tuathail, the former president of the now-defunct NAGP.
Mr Varadkar said that he did not "as standard" keep all of his text messages, so he did not have the text messages between himself and Dr Ó Tuathail, but Mr Doherty argued that those messages should have been subject to Freedom of Information requests.
"It's widely reported that you told a meeting of your parliamentary party that they should be careful of the friends that they choose. That doesn't sound like someone who regrets their actions, Tánaiste. That sounds like the words of someone who is annoyed that they got caught.
"Instead of accepting responsibility for your actions, you just threw Maitiu O Tuathail under the bus and then you decided to reverse over him. Maitiú Ó Tuathail isn't to blame here. He was perfectly entitled to seek this document.
Mr Varadkar rejected that characterisation, saying that he had made it clear on Tuesday that he took responsibility for the affair.
"In my statements on Tuesday I very clearly, and very definitively, accepted responsibility for this, and I used the term sole responsibility. So I haven't sought to blame anyone else. I've apologised for it, I've accounted for it. And I said that I accept responsibility for it."
The Sinn Féin TD asked the Tánaiste if he had deleted the messages between himself and the former union head, something Mr Doherty said would breach Freedom of Information laws.
Mr Varadkar said that he contacted Dr Ó Tuathail over the weekend because Rise TD Paul Murphy had claimed the document was sent on April 2, three days before it was agreed.
Mr Varadkar said that he contacted Dr Ó Tuathail because his recollection was that the document was sent "closer to the 17th".
"When I did check my WhatsApp messages, it wasn't there. You know I don't as standard keep all text messages. I do have a personal email address but anything on that that could constitute a public record, I then forward on to my official account, but I don't as standard keep text messages."