The language has certainly changed. Brian Cowen speaks with a coherence and development of thought rarely seen from his predecessor.

It's not that Bertie Ahern didn't have a complete grasp of European affairs. He just had a difficulty communicating it to the public.

Mr Cowen is keeping his message pretty simple and to the point.

And like Mr Ahern he also appeared to have an intolerance of campaigners against the referendum.

Although labelling the opponents of the Lisbon Treaty as "loo-laas" and the "looney left" was hardly an engagement in debate.

By contrast, Mr Cowen says the No campaigners can express their views, but he will challenge them all the way.

"As the late Daniel Patrick Moynihan said, 'you are entitled to your own opinion, but you are not entitled to your own facts.' Ours is a positive message and we welcome a vigorous debate," he said.

"But we want to make it clear that we have no intention of standing back and letting them distort the treaty or demonise a union which is so important to the success of modern Ireland," he added.

The No campaign may have got out of the blocks faster, but the party machines are now getting into gear.

One by one, the new Taoiseach went through the anti-treaty arguments and showed he was going to ensure claims were challenged.

"The most common tactic has not been to try to persuade people, but to try to confuse them," he said.

In a less than subtle dig at businessman Ulick McEvaddy's claim he's voting No because he found the Treaty impossible to read, Mr Cowen accepted it was a complex document but pointed out this was normal for an international treaty.

"To suggest that you can only support something which is an easy read is absurd and any such treaty would contain many potential problems," he said.

And he fairly hammered home his point on threats to this country's low corporation tax rate.

Describing the "corporation tax scare" as a classic example of the tactics of No campaigners, he said there was nothing in the argument.

It doesn't exist. It is not in the treaty. Gordon Brown confirmed that if there was anything in the treaty that he wouldn't have agreed the treaty in the first place.

"Neither would we. And we are not alone in that. There are others. It isn't an issue in this treaty," he said.

Just 12 months ago though, Mr Cowen was himself warning of the dangers of efforts at European Commission level to bring Ireland's corporation tax in line with the rest of Europe.

The Common Consolidated Tax Base is on the backburner of the European Commissioner Lazlo Kovacs. During the general election campaign, Mr Cowen ominously warned if Fine Gael and Labour got into government the proposal would be more likely to come to fruition because they wouldn't be skilled enough to pull it off.

"There is still no proposal before the council. There has been a lot of work going, but it doesn't have any imprimatur from council. The position is as before.

"Are there are any circumstances under which I would support the harmonisation of taxes under my leadership? I do not believe so," he said.

From scaremonger to calming influence in just a year -- that's quite a journey.

Within his own party, Mr Cowen is using his first campaign as party leader to lay down the law on how he expects TDs and ministers to behave.

He made it abundantly clear he won't put up with any dissent or breaking of ranks.

Mr Cowen feels confident enough to speak on behalf of all his TDs -- a brave move given the past experience with this diverse bunch. "Take it from me that all of the members of the FF Parliamentary Party support this treaty; the membership of our party.

"We are absolutely committed to the ratification of this treaty. It is fundamental to how we think, what our philosophy is.

"And if there were to be anyone -- and I don't know of anybody, but take it hypothetically -- who had a conscientious problem, they would have to consider that outside the context of my parliamentary party," he said.

Certainly, this approach is a marked difference to Mr Ahern. Having been returned to power following the 2002 general election, the first task for the then Taoiseach was getting a declaration guaranteeing Irish military neutrality ahead of the second referendum on the Nice Treaty later that year.

The day after appointing his new Cabinet, Mr Ahern met with then Spanish Prime Minister Jose Maria Aznar -- whose country held the EU presidency to discuss the declaration.

Astonishingly, just 24 hours before going to the EU to help get the referendum passed, he had promoted Eamon O Cuiv to his Cabinet.

When asked why he had appointed Mr O Cuiv to the Cabinet after he voted against the Nice Treaty the previous year, the Taoiseach said that, as a result of what was being done in the Declaration and the Programme for Government, the Galway West TD would work 110pc to ensure the treaty was passed.

In many people's books, Mr O Cuiv should have been sacked from his Junior Minister in 2001 and never darkened the door of a minister's office again for committing such a cardinal sin.

You can take it Mr Cowen's response would be distinctly different.It's doubtful anybody is going to put the theory to the test.The new Taoiseach has made it crystal clear -- he means business.

FSHEAHAN@INDEPENDENT.IE