''The urban dictionary describes kamikaze by way of action as, complete and utter disregard to logic or rational thinking.''
He said Ross was seeking revenge after he felt Bridges had not promoted him as expected and it ended with him being forced out of the party.
''What we see is a desire by him to take down Bridges and ensure that if he, Ross was required to leave Parliament that there would be equal damage to Bridges, his position and his reputation.''
Mansfield said that while on the face of it the SFO had what appeared to be an admission from Ross to being party to fraud, an investigation into the background behind the admissions shows that they are unreliable.
He told the court it was unusual for a lawyer to describe their client as someone who has lied.
''But I so do and that is because it is readily apparent that Ross lied.''
''The very statements the SFO rely on against him can be described simply as lies.''
Mansfield said Ross was Bridges' numbers-man in terms of rallying support in the caucus for his leadership.
He said that Ross was expecting and had been promised a promotion for this, but he did not receive the Shadow Leader of the House role, and he felt betrayed.
''Ross responded (to Bridges), 'My head says suck it up but my heart says go kamikaze. Head wins, I'll suck it up.'''
''There is the first lie. The greatest of respect to Mr Ross, there is the first lie to Mr Bridges because the head didn't win, the heart won.''
Mansfield said it was perfectly clear from that point on that while Ross presented outwardly as being loyal and on the inside of Bridges' trusted team, the reality was such that he set about seeking to destroy the confidence that others within the National Party had in Bridges and also public confidence in his leadership.
Mansfield said information leaked to the media by Ross about Bridges caused significant political embarrassment to Bridges.
He said Ross was suffering from mental health issues at the time.
''Ross was prepared to lie in order to save his position within the National Party and his position within the House in the first instance, but when that was not possible, as we see in the evidence, to lie in order to further his desire for revenge against Bridges and if he was to go, so was Bridges.
''The only way he could cause destruction or damage to Bridges was to take himself down, by implicating himself also.''
Mansfield said this was when Ross asserted that Bridges had requested that he (Ross) receive and split up one donation from one donor so that it could be misreported in such as way that the public wouldn't become aware of the donation or the donor.
''In reality, given the drive to take down Bridges, Ross obviously needed to implicate or involve himself in the said fraud and that is what he sought to do.''
''What I hope is perfectly apparent from the evidence, rather sadly for Ross is the reality that when he made that admission he cared little about himself and hence whether it was an admission against his own interests.
''He was fixated on seeking revenge.''
The seven-week trial has now finished, with Justice Gault reserving his decision.
- RNZ
