Gerry Adams climbs up a ladder to put up a Sinn Féin poster on a lamp-post outside Government Buildings.

The party's Dublin European election candidate Lynn Boylan is commandeered to hold the stepladder steady, which she does a little nervously.

A small group of party acolytes stand around to admire the phenomenon of an Irish politician sliding up a slippery pole.

The last Irish politician of note to shin up a lamp-post was Michael McDowell. People remember his famous 2002 stunt (Single Government, No Thanks) but he tried it again in 2007. Sic transit gloria mundi. The Progressive Democrats were eviscerated. Looked at with a long view, that successful stunt of 2002 was the last sting of a dying wasp.

Has Gerry Adams's moment passed? There was a time when every lamp-post in the country would have featured that unmissable combination of beard, spectacles and toothy smile. Not any more. Adams is leader of the party, but when you travel to Dublin West it is the image of the party's deputy leader, Mary Lou McDonald, that crops up everywhere beside byelection candidate Paul Donnelly.

Adams has been at the helm of the republican movement (you can define that as widely or as narrowly as you wish) for 30 years, maybe more. Are we seeing the beginning of a transition where he moves from being the lead actor to playing a cameo role, what the Tories call a grandee?

Everybody forgets quickly how cyclical politics is. A big change happens in the political structure and people begin to think of it as permanent, when it is only actually permanent until the next big change happens.

Sinn Féin itself is a good case study. It had a meticulous strategy for growing the party in the South that looked foolproof until it hit the doldrums in 2007 and in 2009.

Now the party looks to be on an unassailable and inevitable rise, but are the gains real? Are the opinion polls, with their oscillating conclusions, that accurate? Even if they are, is it permanent, or might a chunk of the 15 per cent of floating voters move on elsewhere next time?

But with Sinn Féin, it's the strategy of American civil war general Nathan Bedford Forest that comes to mind. Who wins is the side that can "get there fastest with the mostest".

So, for political expediency’s sake, it is McDonald (the politician du jour) who will star in posters.

That's not to say she's supplanting Adams. He's still the figurehead, and those who think his Dáil performances act as a drag on Sinn Féin sometimes don't appreciate it doesn't even come on the radar outside Leinster House.

Besides, Adams didn’t make it to the top of the republican movement solely on the basis of his PR skills. His skills as a strategic thinker remain core. In conversation, he is quite candid in his assessment of supposedly favourable opinion polls , and readily admits his arrest and questioning in the McConville case might adversely affect the party’s vote.

Spending a day with Adams is a different experience than spending it with Enda Kenny. There are a few moments of levity, but there is none of the high octane, high-five stuff.

The morning starts with Adams launching the party's local election manifesto. What emerges from this is more questions on his arrest and questioning, as well as a full-frontal attack by him on Independent Newspapers for what he contends is a "scurrilous" article on his evidence during his brother's criminal trial for serious sexual assault. He discloses he has instructed the Belfast defamation specialist Paul Tweed to issue proceedings against the media group.

His group then saunters to Government Buildings for the photo op with a ladder and lamp-post. Boylan is there with trademark sunny smile. She joined Sinn Féin in 2005, long after the Belfast Agreement, and so is from the civvy street generation, supposedly unfettered by legacy issues.

There is no ambivalence in her views on the legitimacy of the republican struggle or on Adams’s arrest. Ditto with McDonald. Out on the canvass later, you put to her that her comments on the Adams arrest were hardline and at variance with the party’s position on policing in the South. Her argument is that her motive is to defend the peace process and its integrity. If people view this as hardline, so be it.

In the afternoon, the party canvasses in Dublin West with byelection candidate Paul Donnelly, who is chatty and accommodating. Two other candidates, Natalie Treacy and Congo-born Edmond Lukusa, join Adams outside Mary Mother of Hope primary school in Ongar. At 2.30pm, hundreds of kids emerge from the school in a happy wave, mobbing the canvassers.

Dublin 15 is the most ethnically diverse place in the country. You can see proof of it here, and in the four schools nearby in this massive new town near the Meath border. These are children of parents from dozens of nationalities, but their accents and disposition are local. Adams stands still as a lighthouse amid this sea of children, chatting quietly to the parents that stop when they recognise him.

Later they move to Roselawn, a middle class area near Blanchardstown's old village. They were going to do the shopping centre but divert when they see that Ruairí Quinn and Joan Burton are already there. Instead, they go into the estates.

It’s a lovely day in May. The backdrop of sounds is a classic suburban summer hum, of hedges being clipped and lawnmowers droning. There is a smell of freshly cut grass. Such estates are not traditional territory for Sinn Féin in Dublin.

McDonald joins them for the canvass. People greet her warmly, but it is the iconic Adams who is most pointed at. A man comes out to tell McDonald he’s going to vote Sinn Féin for the first time in his life because of the property and water charges. His wife comes out, gives McDonald a kiss of greeting, and agrees.

Elsewhere, the welcome is not quite so warm. The rejections are polite though: “I’m sorry but I don’t have the time to talk to you.” There is no sign of outright hostility.

The effect of Adams’s arrest will be intriguing. Will it act as a brake on Sinn Féin’s forward momentum, or will it show that voters have no illusions about Adams’s role during the Troubles - but no longer see it as an issue?

Low turnout in all elections will also be an issue, and could affect Sinn Féin’s vote more than most. McDonald points to that, as does Joan Burton who forecasts a very low turnout.

The canvass ends. Adams hops into the passenger seat of a car heading to Cork. McDonald speaks to him at the window, reminding him he shouldn’t complain - after all, she has the children to collect and the shopping yet to do.

In homage to Ursula Halligan's TV3 documentary on Sinn Féin: it's presumably cheerio for Adams; Cheerios for his deputy leader.