Adams slammed for Smithwick comment
Politicians on all sides in Dublin and Belfast reacted in disbelief after the republican leader said that Chief Superintendent Harry Breen and Superintendent Bob Buchanan effectively drove themselves to their own death.
An eight year tribunal found an IRA mole in the Garda station in Dundalk tipped off a terrorist hit squad that the men were attending a meeting in the town on the day of the murders, March 20 1989.
Mr Adams claimed the RUC men thought they were immune from attack and had "a laissez-faire disregard for their own security".
The Republic's Justice Minister Alan Shatter said the Sinn Fein leader's comments were nauseating.
"There should be no doubt as to where responsibility lies. The responsibility lies at the hands of individuals who carried the gun," he said.
"This was a case of brutal pre-meditated murder by the Provisional IRA and nothing Mr Adams says will ever change that fact," she said.
Unionist politicians said Mr Adams' remarks called into question his judgement, and the resounding criticism is bound to heighten concerns within Sinn Fein about his leadership credentials.
He is already under pressure from critics for constant denials of IRA membership or involvement in the 1972 murder of Belfast mother-of-ten Jean McConville levelled at him by former republican allies who have since died - IRA commander Brendan Hughes and Old Bailey bomber Dolours Price.
And in the last months Mr Adams has been at the centre of scandal over his handling of abuse. He knew as far back as 1987 that his brother Liam was a paedophile, having raped his own daughter, Gerry Adam's niece Aine Dahlstrom. However, the Sinn Fein chief only made a police statement in 2007.
Opposition politicians in Dublin also claim he is aware of at least two other cases of sexual abuse dealt with internally by the republican movement.
A second outburst on the Breen-Buchanan murders by Mr Adams, during debates in the Irish parliament, sparked a severe backlash for him and Sinn Fein.
"These were brave officers doing their duty as they saw it, in the same way as the IRA volunteers would see themselves as doing their duty as they saw it," he said.
He added: "You can't just draw a line and say there was a good IRA back in the day throwing powder puffs at the British and that there's an IRA, which has departed the stage which behaved in a more cruel way."
Mr Adams refused to apologise or withdraw any remarks.
The report on the Smithwick tribunal is a damning expose of collusion, bad policing and misguided loyalty in the Garda.
It said a Provo mole leaked information that the officers were in Dundalk station for a meeting on the day of their murder although the source of the collusion has not been identified.
It is suspected there were two people in the station working for the IRA.
Mr Shatter, who has apologised over the collusion, said: "It is quite clear to me that he (Mr Adams) was trying to suggest that two respected officers of the RUC... were themselves responsible for travelling a road in the Republic in which they were assassinated and were themselves responsible for their own deaths."
The tribunal accused current Garda chiefs of trying to protect the reputation of the force by undermining a retired superintendent who testified that he passed intelligence on a death threat against Mr Buchanan to the highest ranks in the force the year before the attack.
Ireland's police chief, Garda Commissioner Martin Callinan, apologised and said there had been a betrayal from within the force.
"To think that any member of my force would engage with the IRA at any level is beyond comprehension," he said.
"And to betray both themselves and my organisation in such a fashion is beyond me.
Jeffrey Donaldson, Democratic Unionist MP, rejected any suggestion the Breen-Buchanan murders were a one-off with suspicions long held about the killings of a judge and his wife, Sir Maurice and Lady Cecily Gibson, in a roadside bomb at the border as they drove home from holiday in 1987, among others.
"I do not think collusion was restricted to one instance,"
Mr Donaldson also raised the case of Co Louth farmer Tom Oliver who was murdered by the IRA in 1991 and branded an informer.
"Adams' words also fall into an increasingly prevalent pattern whereby republicans seem determined to retraumatise the victims of their terrorism," she said.
Ulster Unionist leader Mike Nesbitt said Mr Adams' assessment of the IRA murders is grossly insensitive.
"Sinn Fein are the self-proclaimed party of respect. They may need to re-evaluate that," he said.
SDLP justice spokesman Alban Maginness said Mr Adams' comments showed callous disregard for the families.
"To blame victims for being murdered and try to apportion responsibility to them for being killed is just vile," Mr Maginness said.
SDLP leader Alasdair McDonnell said: "The argument that Harry Breen and Bob Buchanan somehow brought these events upon themselves is warped and totally illogical."
Meanwhile, Irish Taoiseach Enda Kenny, on an official visit to Japan, said he would meet the families to discuss the report if they felt that was appropriate.
"It is a revelation of another dark patch in Ireland's recent history," he said.
On the tribunal's damning criticisms of the current Garda force where the judge found "loyalty is prized above honesty", Mr Kenny said: "The judge makes comment about a culture. It is true that in the past we have different reflections of culture in Ireland... we are in a different space now."
Mr Kenny said he fully endorsed an apology on behalf of the Government from Mr Shatter and Tanaiste and Foreign Affairs Minister Eamon Gilmore.