The national mood here has turned nasty in the last few weeks, a fact which was evident again last weekend.

On Saturday Tanaiste (Deputy Prime Minister) Joan Burton, who had gone to a graduation event in Jobstown, a deprived suburb on the west side of Dublin, was trapped in her car for several hours by water charge protestors. In ugly scenes the protestors pushed back Gardai (police) and shouted slogans while they banged on the roof of the vehicle.

From the inside it must have been very intimidating, since there were only a few Gardai on duty trying to hold back a small but very hostile crowd. Despite the eventual arrival of reinforcements this went on for over two hours.

Finally, the Gardai transferred Burton to other vehicles and managed to get her away. During the confrontation she was hit with a water balloon and two Gardai were injured by the "peaceful protest."

The next day, Sunday, Taoiseach (Prime Minister) Enda Kenny was at a book launch in the city center and again water charge protestors surrounded the entrance to the venue and attempted to block his car from leaving. This time the Gardai were better prepared. But the same aggression, running battles with Gardai, slogan shouting and abuse were present.

On Monday it was the turn of the Minister for Finance Michael Noonan who was faced with an angry crowd outside an event in Limerick. And the new Minister for the Environment Alan Kelly (who has responsibility for water) had death threats phoned to his office on the same day.

There have been similar incidents over the past few weeks. These included an attempt to disrupt a meeting a week ago in the GPO where political leaders were announcing plans for the 1916 commemorations. Protestors outside banged on the windows and screamed abuse so loudly that those inside found it difficult to continue.

All of this shows an aggressive, intimidating side to the campaign against water charges. For that we can thank some of the left wing pressure groups and Sinn Fein who are now vying with each other to piggyback on the national resentment against the charges.

Very few people here support this kind of behavior, even if they don't like the new charges and joined the peaceful marches around the country a few weeks ago. Whatever people think of the water charges – and there are valid arguments for and against – it is clear that both Sinn Fein and a few radical left deputies in the Dail (Parliament) are exploiting the issue as much as they can for cynical political reasons.

Sinn Fein was outflanked by a radical left, anti-water charges candidate in the recent by-election in the area where Burton was trapped in her car on Saturday. They are determined this is not going to happen again and so they’re much more aggressive in their campaign.

The result is that the recent, supposedly spontaneous, protests targeting ministers have taken a sinister turn with the kind of shaven-headed heavies we used to see providing "security" at Sinn Fein events now very much in evidence.

At the time of writing, the government's revised package of water charges is still unknown, but it's expected the new charges will be about half what people were initially being asked to pay. It seems likely that this will defuse much of the public anger against the charges, but it's not clear yet whether it will isolate the Won't Pay radicals.

It's no coincidence, of course, that this sharply increased aggression has emerged at a time when Sinn Fein has been under much sharper scrutiny over its handling of the Mairia Cahill abuse case.

The nasty scenes on the streets in recent days were matched last week by extraordinary scenes in the Dail when Sinn Fein defied the speaker and staged a sit-in for several hours, shutting down the business of the house.

From the Sinn Fein perspective they were simply trying to force Burton to answer specific questions on how the new water charges would be implemented, which she had failed to do.

From the government's perspective Sinn Fein was simply trying to deflect attention away from the Cahill case and avoid answering the embarrassing questions for them that had been raised in the Dail on the issue on the previous day.

But of course it's not that simple. It never is, particularly in the run-up to an election. And even though we could still be a year and a half away from the election, all the parties are already using every opportunity that arises to get an advantage with voters.

Sinn Fein accepts that Cahill was abused by an IRA man and claims they tried to help her at the time. But they claim to know nothing about IRA abusers being facilitated to evade justice and get out of the North.

In particular, Gerry Adams denies knowing anything about IRA men who were abusers being shifted in secret to the south. Sinn Fein claim that the concentration by the government on the issue at this particular time is bogus and politically motivated.

They say that instead of having Cahill's interests genuinely at heart, the other parties in the Dail are using the case as opportunistic attack on Sinn Fein. They claim the government and Fianna Fail are doing this because they are alarmed by Sinn Fein's rise in the opinion polls, the latest of which makes Sinn Fein the most popular party in the country.

So where does the truth lie? The truth is that there is some truth, but not the whole truth, on both sides.

Only someone who is very politically naive would deny that there is a political aspect to the high profile way the government parties and Fianna Fail are using the Cahill case to damage Sinn Fein. That does not mean, however, that Sinn Fein does not have serious questions to answer on the case.

Clearly they do, and the more they try to dodge these questions the more the media here pursue them on the issue, which is one reason why the case has become such a huge story.

Sinn Fein's assertion that the timing of all this is suspect has one major flaw. Cahill chose to make her case public at this stage because she had exhausted all the other possibilities she had of getting justice. It was her decision to go public now, and she has raised very serious questions for Adams and Sinn Fein by doing so in such a courageous and articulate manner.

Sinn Fein's other claim is that it is hard to take seriously the concern of the main parties for the case, given their poor track record on all the historic abuse scandals that emerged here in recent decades. But that line of defense is fatuous and people here see through it. The Cahill case is not something that happened in the 1950s.

The sinister aspect to the water protests over the past week and the attempt to bury the Cahill case have confirmed for many people here that Sinn Fein is still more a Stalinist movement than a genuinely democratic party. The "jokes" about sending in the heavies to sort out Independent Newspapers made by Adams at the recent $500-a-plate dinner in New York are more of this intimidatory attitude.

One thing is sure. Many of those who were lining up at that dinner to have their picture taken with Adams would be appalled by the high tax regime that Sinn Fein wants to introduce here to cover things like water services.

Like the other radical left activists fomenting the "peaceful protests" over water charges, the socialist agenda which underlies their actions, if implemented, would turn Ireland into a sort of Cuba without the sunshine.

What the past week here has shown is that some nasty things are now coming to the surface. Whether the waters remain choppy will become clearer later this week.