Ireland's prime minister has indicated Dublin will provide no political support for Sinn Féin in its opposition to Gerry Adams's arrest over the murder of the IRA victim Jean McConville.
The taoiseach, Enda Kenny, said on Friday night he was more concerned about the safety of McConville's children, some of whom have expressed fears they would be killed if they passed on the names of the IRA unit which they say kidnapped their mother in December 1972.
During the peace process from the IRA ceasefire 20 years ago until the restoration of power-sharing in 2007, successive Irish governments have been accused of secretly urging the British and US administrations to turn a blind eye to continuing republican violence, much of it directed against their own communities in Northern Ireland.
But Kenny called on Adams to provide any information he has about the McConville killling as the former West Belfast MP spends another day in police custody being questioned over the woman's murder and secret burial during the bloodiest year of the Troubles.
The Police Service of Northern Ireland went to court on Friday to ask a judge to give its detectives an extra 48 hours to hold the Sinn Féin president at the serious crime suite in Antrim police station.
Commenting on Adams's continuing arrest, the Kenny said: "PSNI is not the RUC and, in that context, anybody who has any information about the 10 to 12 people and those who ordered them to take out Jean McConville to have her murdered and have her disappeared … have a duty and a responsibility now to give that information to the PSNI.
"I now expect Gerry Adams, the same as anybody else as a citizen of this country, to give full and thorough and comprehensive information about what they know."
On Michael McConville's warning that he could be killed if he passed on the names of those who stormed his home in west Belfast just before Christmas in 1972 to abduct his mother, the taoiseach said: "It concerns me. It shows the rawness of the emotion that is still there and the fear and the anxiety and the concern of many people about speaking out."
Kenny's remark underlines a major shift in Dublin's policy towards Sinn Féin, which is partly motivated over fears among governing parties about the rise of Adams's party in the opinion polls.
In the years after the IRA ceasefire the Irish government had an unofficial policy of playing down continuing IRA violence.
Just two years after the 1994 ceasefire an IRA unit shot dead Jerry McCabe, a police officer from the Garda Síochána, in Co Limerick during a botched robbery.
Irish government ministers and officials from the department of foreign affairs initially blamed the murder on dissident republicans or the Irish National Liberation Army when in fact it was members of the mainstream Sinn Féin-aligned Provisional IRA who were responsible.
The attempt to cover up the IRA's role in the McCabe murder caused outrage among the Garda Síochána, with representatives of its middle-ranking officers stating there was "seething resentment" over the government's official line at the time.
Sinn Féin staged a protest outside Antrim PSNI station on Friday night against the police's decision to hold Adams at least until Sunday evening.
Gerry Kelly, the former Old Bailey bomber, IRA Maze prison escaper and influential voice within the mainstream republican movement, said there was "a growing anger with every single hour" that his leader and close colleague was detained.
Kelly said: "The arrest was uncalled for and certainly the extension is uncalled for. I was out canvassing last night and the anger was palpable – I'm getting this on the doors from people, not all of whom are Sinn Féin voters."
The party continued to insist over the weekend that the arrest was timed to coincide with elections this month and designed to cause it damage particularly among voters in the Irish Republic.
But the leader of the Ulster Unionist party has challenged Martin McGuinness, the Sinn Féin deputy first minister of Northern Ireland, over his claims that "dark forces" opposed to the peace process within the PSNI were behind the arrest.
Mike Nesbitt said on Saturday: "If he really believes what he's saying then he has a duty and an obligation as deputy first minister to do something about it and produce the evidence.
"Martin McGuinness and the republican movement can't cherrypick their support for the police. They either support the police or they don't.
"It is one thing to scrutinise the police – it is totally unacceptable for their support for police to be conditional on getting political policing in relation to republicans, which Martin McGuinness seems to be suggesting."
McGuinness hinted on Friday that Sinn Féin may review its support for the PSNI if Adams is held for much longer or even charged in connection with the McConville murder.
Withdrawing backing for the PSNI would trigger a fresh crisis in the power-sharing regional government in Belfast.
The republican party's decision to sign up to support the PSNI and the judicial system were the key foundation stones of the St Andrew's agreement in autumn 2006.
This led the following year to the once unthinkable scenario of McGuinness as deputy first minister working alongside Ian Paisley as first minister in a political double act nicknamed "the Chuckle Brothers" because the two former enemies could not stop smiling when photographed and filmed beside each other.
Despite hints of a U-turn on policing policy by McGuinness, the deputy first minister went on with his normal ministerial duties on Friday night.
He joined the first minister and Democratic Unionist leader, Peter Robinson, at Ravenhill to open a new stand at the home of the Ulster rugby union team before their Pro12 clash with Leinster which the Belfast side lost.
Sinn Féin's Alex Maskey, a veteran Northern Ireland assembly member and former lord mayor of Belfast, told Radio 4's Today programme on Saturday that anger over the Adams detention did not mean the party was pulling out of the policing arrangements in Northern Ireland.
The Belfast South MLA said: "Martin McGuinness actually didn't say that we will withdraw support for policing, we will not withdraw support for policing of course, because we do support policing.
"What we will continue to monitor and review is our relationship with the PSNI if indeed we have a situation which we believe is continuing at the moment, where we have a small element of people involved in policing who are politically motivated, who have a hostile attitude to our party, who have been taking very retrograde steps in relation to how they deal with policing."
