When Bertie Ahern gave the interview about the 30,000 for his house renovation to Vincent Browne last Thursday, he was not on his home ground. He was unprepared. He was facing a forensic rottweiler in a public scrum.

It stands to reason that the Dobson interview would be better. Except that it wasn't. It started with a lengthy whinge about accusations made against the Taoiseach and was memorable for an overcome-by-emotion moment in the middle. It had a half-complaining, halfingratiating tone which produced a viewer reaction one notch down from enthusiasm. Viewers didn't say: "This man is innocent, leave him alone." They said: "This puts my molars on edge, leave him alone."

The Vincent Browne assault, mid-manifesto, was quite different. So different, and so productive for Bertie Ahern, it immediately generated the mad conspiracy theories characteristic of Fianna Fail controversies: Vincent Browne actually did Bertie a favour, so he did. He lanced the boil for Bertie. He did it to publicise his own interview that night. Or maybe he did it to vindicate something he'd said in the current issue of Village magazine.

The conspiracy theories miss an essential truth about Vincent Browne, which is that he needs no external motivation to act like a medieval witchfinder. The comment Lady Caroline Lamb made about Byron applies: Vincent Browne is mad, bad and dangerous to know, and social friendship with him doesn't protect anybody from his madness, badness and danger. As PJ Mara found out when he started his smiling "Now, Vincent, don't be a bad boy or I'll have to call a time-out on you." Browne set aside his normal repertoire of snorts, wheezes and sighs and delivered a rebuke of statesmanlike clarity. He lynched Mara on camera.

However, the very fact that Mara was caught on camera at all lynched the press conference. A panning shot picked him out of the shadows (as one political correspondent muttered at the time) like a sequence from the old Nosferatu movie.

Nosferatu, the Undead. The Vampire.

The presence, quite apart from the unproductive intervention of Mara, created the perception of an unbroken continuum between Charles Haughey's massive financial depredations and Bertie Ahern's foosthering which did the latter no favours at all.

Candidate Jim O'Leary caught it in the neck last week for putting up posters showing Charlie Haughey and Bertie Ahern side by side. It wasn't fair, Fianna Fail said, to visually link the two. Which begs the question of why the party itself contributed such a telling picture, of a man inextricably linked with CJ trying to provide the same service for Bertie.

Overall, though, the encounter showed the Taoiseach giving a more vivid and authentic performance than he had given, months earlier, to Dobson. There was real engagement, with the Taoiseach demanding that Browne acknowledge Bertie's right to do whatever the hell he wanted with his own money. He wasn't tetchy, doing the miserable little snaps he does when he's not quite in the right, but knows he isn't fully in the wrong. He wasn't maudlin and emotionally manipulative.

He was straightforwardly mad as hell, sure of his facts and concentrated on ramming them straight down the Browne neck.

It was a case study in communication, proving, first of all, that preparedness is the best thing any communicator has going for them. Bertie Ahern has a photographic memory and has been through the Tribunal transcripts often enough to imprint every comma on his brain.

But he'd been prepared for the Dobson interview, too.

The key differences, this time, were surprise and tone. Instead of Dobson's 'Sorry about having to ask you this stinker' tone, Browne's 'You can't seriously expect me to swallow this bilge' approach sent an almost visible adrenalin surge through the Taoiseach, turning him lucid and lively. Instead of iffy television with a small strand of self-serving creepiness, he delivered media excitement of such intensity that the whole encounter seemed to last only three minutes.

Never mind the pints of Bass. What Bertie clearly needs, to relax and give him focus, is a few pints of adrenalin.

It came too late to influence weekend opinion polls. It came too late to prevent the imprinting on the public mind of that dire earlier shot of his smirking, silent refusal to answer a question at a press conference.

It was, nonetheless, a hell of a performance, and a potential turning point in a campaign dogged by tribunal leaks.

Whether it turns out to be a turning point . . . as did the first, Dobson interview . . . depends crucially, not on credibility, but on credulity. Many of the journalists present found the Taoiseach credible.

But . . . and here's the rub . . . they're wary of their own credulity. They don't want to get caught having believed Bertie if later leaks pull the rug from under him.

The general public would like to believe Bertie this time, as they did when he gave the Dobson interview. Voters are bored with the complexity of the transactions involved, and discomfited by ploughing around in anyone's messy private life. But they don't want to feel they've been conned.

What Fianna Fail calls an "orchestrated campaign of leaks", combined with Vincent Browne's successful breach of the Taoiseach's stated determination to answer tribunal questions only in the tribunal, could have one of two effects. It could confirm the "don't want to hear any more of this stuff" mindset. Or it could establish a "no smoke without fire" mindset.

The one thing that's clear is that not even the best-oiled PR machine in the country can make a party manifesto more interesting than a potential scandal.

Although coverage this past week . . . rightly or wrongly . . . has queried if the Fianna Fail PR operation is as well-oiled as in the past.

That started with a report by Micheal Lehane on Sean O'Rourke's Sunday night programme The Week in Politics showing the Taoiseach reading a script which, the reporter pointed out, had been handed to the journalists present four hours earlier. It also offered a close-up of the misprint in the main heading of that speech, suggesting this indicated lack of preparedness for the dawn raid on the Aras.

While RTE radio news programmes such as Morning Ireland and Mary Wilson's Drivetime did scrupulously straight examinations of what was going on, Newstalk's current-affairs presenters did free and frank editorialising about Bertie's body language and refusal to answer questions . . . "that doesn't look so good", one of their early morning presenters opined.

"I would want to clear my name, " the other said. "I'd be saying: "Bring it on."

All of which took the media heat off Fine Gael's decision not to have their leader head up their daily press conferences. At any other time, the decision to front Frank Flannery and Ciaran Conlon would have been highly controversial. Last week, however, not only did they get away with it, but the overwhelming message delivered by the Fine Gael campaign was visual, showing Enda Kenny demonstrating what was once described as Bill Clinton's unique mix of campaigning skills:

energy, stamina and joy. Pat Rabbitte wasn't far behind him, and the Greens managed to look happy but not smug.

In media terms, the Progressive Democrats almost fell off the edge. They got coverage without traction . . . until, of course, Michael McDowell started his period of reflection.

Fianna Fail is livid over the first week's coverage, the unfairness of which, as they see it, was best exemplified by two national newspapers choosing to run a photograph of their leader with his eyes closed, when those newspapers had a wealth of more favourable shots. They're furious with the PDs for wobbling, and even more so for their confirmation that they're meeting the issue in voter encounters.

The old hands are pointing out that the issue in the first week of an election rarely survives until, or influences, the last week, but are fearful that candidates in marginal constituencies will start to seek personal publicity by distancing themselves from the leader.

The opposition parties know that shutting up and letting the media do the heavy lifting has worked. Up to this point. But will that pattern continue?

More than the weather could change this weekend.