IN MANY WAYS Alan Shatter and Sean Barrett are similar men.

Both were elected to the Dáil for the first time in 1981 as Garret FitzGerald led Fine Gael to what was, at the time, its greatest ever election performance - going from 45 seats to 65 and booting Charlie Haughey out of power.

Both have been in the Dáil ever since - save for the five years following 2002, when Michael Noonan led the party to what was its worst ever election outing. Barrett retired for that outing; Shatter was retired by the public.

Both have an impressive portfolio of financial assets, outside of their lives in politics. Shatter has the biggest ever property portfolio of any cabinet minister, while's Barrett's previous career in the insurance industry has served his wallet well.

And perhaps that's because both men are firmly driven by their sense of correctness and a refusal to allow an argument to rest if they have not forced an opponent into submission.

It's a habit that ultimately led to Shatter's downfall - and to his many scandals, in particularly that surrounding his disclosure of Mick Wallace's encounter with the Garda Traffic Corps at the Five Lamps in Dublin.

The then-Justice minister was debating with Wallace on RTE's Prime Time about Gardaí and the use of discretion in dealing with alleged motoring offences. But despite arguably having the upper hand in the debate, Shatter had to go for the jugular, and used information which both the Data Protection Commissioner and the Dublin Circuit Civil Court says he shouldn't have used.

That's a hallmark of the way Shatter goes about his business. Perhaps it's an approach that has worked well in his career in the courts, but Shatter feels it necessary not just to win every argument, but to simply demolish his opponent, and suffocate them with reason and argument.

It was that instinct that led him to tell RTÉ viewers that Wallace himself had benefited from Garda discretion, when he was let off with a gesticulated warning for holding his mobile phone while driving.

A thirst to be proven right

Sean Barrett has a similar approach to the way in which he runs Dáil business. Although the rules of the house are generally a bit simpler to interpret than the laws of the land, Barrett's standpoint on them is clear: it's his way or the highway.

That's why it was hardly much surprise last week when, having decided that the Dáil would not be allowed to debate the Terms of Reference for a former Commission of Inquiry, Barrett was not for turning.

It didn't help that he was out of the country when his ruling became known - or that he decided to give an ill-advised interview to RTÉ last Friday where he not only gave an incomplete explanation of his rationale, but also cast aspersions over the reasons why the opposition might disagree with him.

He's shown a similar tendency in the past, when his arbitration of Dáil Standing Orders (basically, the rules governing the Dáil and its debates) has proven contentious.

Recently the Technical Group has raised legitimate questions about what appears, on the outside, to be an inconsistent application of those standing orders. Lucinda Creighton and Peter Mathews asked to join the Dáil's technical group and were told there was no problem with that - the rules, Barrett said, permitted them to do exactly that.

No problem there - but for the fact that the other rules around Dáil participation seem to suggest that a TD's affiliation is set in stone after each election. This would mean that Creighton and Mathews would be barred from the technical group, as they were still officially considered to be part of the Fine Gael parliamentary party.

When the Technical Group's whip Catherine Murphy tried to raise the issue on the floor of the Dáil - simply looking for guidance from the Ceann Comhairle as to the basis for his ruling - she was shouted down and told to raise her objections at the Dáil's procedural committee. 

But when Murphy argued that this was not possible and the matter would never be raised there, Barrett decided to initiate the process by which she was kicked out of the house. Thomas Pringle and John Halligan also tried to raise the same concern, and were likewise suspended from the House, which was eventually abandoned for the day to try and defuse the situation.

Only a few weeks later, when Mary Lou McDonald was on the verge of instigating her four-hour sit-in that brought the entire chamber to a halt, the Ceann Comhairle arguably did his bit to antagonise the situation - deciding to suspend the Dáil indefinitely, instead of for the usual formulaic 15 minutes that follows any significant disorder.

One major difference: knowing when to stop

It's probably not that much of a shock that Barrett would follow Shatter's lead and take every opportunity to assert the correctness of his decision - and agree to a last-gap radio interview from the departure lounge of Dublin Airport last week.

But it is a sign of a perhaps wiser man that Barrett at least knew this tactic would end in disaster - and a motion of no confidence from a rightfully angered opposition - if he did not lament and retract his comments that FF and SF were ("of course") out to get him.

The Ceann Comhairle's voice almost quivered as he admitted there may be more than one way to interpret the Standing Orders - thereby justifying the complaints of the opposition in the first place.

But as for Shatter - one can only but wonder just how much more damage he can inflict on a government he is no longer even a part of.

Enda Kenny has a simple explanation about why Shatter was given early access to cabinet decisions that nobody else saw for a month. He says it was simply to demonstrate to the sulking ex-minister that, no matter how much he protested, the Terms of Reference for the O'Higgins Commission into alleged Garda malpractice would not be changed so as to exclude a scrutiny of his performance.

But there is also an interesting question there. Was Kenny not aware of the poor optics of giving details about a cabinet decision to a sitting TD and former cabinet minister, a month before the rest of the Dail was made privy to the same decision?

And is this not a subversion of the whole inquiry process, where the very man to be investigated is more aware of the parameters of that investigation than the very people who are setting it up?

Shatter's primal habit of needing to prove his correctness is now leading him to a second appeal of the Data Protection Commissioner's ruling on Mick Wallace. Instead of embracing a commission of inquiry which could ultimately exonerate him of any wrongdoing on Garda malpractice, he is now already choosing the tactic of obstructing its existence at every turn.

Even outside of cabinet, it remains to be seen just how much damage Shatter's headstrong thirst for vindication will ultimately cause.