Elements of the Democratic Unionist Party (DUP) hark back to the days of unionist rule and hope to undermine the North's power-sharing government, Sinn Féin claimed today.
Deputy First Minister Martin McGuinness used a speech at a major event commemorating the 1960s Civil Rights Movement to launch an attack on the DUP.
He called on DUP leader Peter Robinson to agree a deal to secure the government and warned that failure to share power would see unionists robbed of any political control.
The Civil Rights movement protested against anti-Catholic discrimination by the then unionist government, but it was attacked by loyalists and police in scenes that preceded the outbreak of the Troubles.
Mr McGuinness told an international conference in Derry marking the 40th anniversary of the Civil Rights campaign that some unionists still believed the period of unionist rule was a "golden age".
"That mindset - of no surrender and not an inch - still exists in some elements of political unionism today, and especially within the DUP," said Mr McGuinness.
"The fact is that there are still those within the DUP who do not agree with power-sharing as a concept or as a matter of political practice.
"They do not accept that the days of unionist majority rule are gone and gone forever.
"They believe that by stalling and delaying they can hollow out the Good Friday and St Andrews Agreements. And that is what is at the heart of the current crisis."
The DUP and Sinn Fein are divided over a range of issues including the devolution of policing and justice powers to the Assembly. The dispute has seen republicans block meetings of the Executive since June.
But Mr McGuinness said: "If one party does not believe in partnership government and power sharing on the basis of equality then it is they who are placing the political institutions at risk.
"The Unionist political system needs to understand and come to terms with the reality that life has changed for everybody.
"The only way any unionist politician will ever hold any semblance of real political power now or in the future is in partnership with nationalists and republicans."
Mr McGuinness said he had attended the British-Irish Council meeting in Edinburgh last week despite the deadlock, but was disappointed the DUP blocked yesterday's North-South Ministerial Council after an Executive meeting was cancelled.
He said that since Mr Robinson emerged as leader of the DUP in June his party had yet to engage in meaningful negotiation and had cherry-picked from the St Andrews agreement.
Mr McGuinness claimed this analysis was supported by recent comments from British prime mnister Gordon Brown and former Taoiseach Bertie Ahern.
"If partnership government is beyond the DUP then it will fall to the two governments to take the necessary decisions and implement the necessary policy changes to ensure political progress in the all-Ireland context envisaged in the Good Friday and St Andrews Agreements," he said.
"The resolution is DUP agreement to work the partnership arrangements and to agree a timeframe for the transfer of power on policing and justice."
The DUP has said there is a lack of confidence in the unionist community for a move on policing, but Mr McGuinness said this was a bogus argument.
"I believe that an agreement forged between myself and Peter Robinson would send out a powerful and hopeful message for the future," he said.
"But if we are to move forward it will take political courage and political leadership. It will need real and meaningful partnership government and power sharing."
His comments came as Northern Secretary Shaun Woodward said the two governments remained ready to help, but believed the parties could yet find a way out of the deadlock.