The Democratic Unionists will bid to suspend the Assembly today or collapse Northern Ireland's power-sharing government following a murder by IRA members.
Political institutions hang by a thread after the country's largest party vowed to resign from the ministerial Executive if business is not frozen at the devolved parliament at Stormont.
DUP First Minister Peter Robinson wants all parties to focus on crisis talks aimed at dealing with the remnants of paramilitarism in Northern Ireland as well as issues left over from the peace process.
He issued his ultimatum after the arrest of three senior republicans, including Sinn Fein's northern chairman Bobby Storey, over the fatal shooting of former IRA man Kevin McGuigan.
Despite unionist calls on Northern Ireland Secretary Theresa Villiers to step in and adjourn the Assembly for four weeks the British Government has been reluctant to intervene.
Mr Robinson said if other parties in the Assembly did not back the adjournment move in a crunch vote today, or if the Government did not act to suspend proceedings in the absence of that vote, then he and fellow ministers would resign immediately.
With the DUP unlikely to garner sufficient support for the move among the other parties, and the Government as yet showing no inclination to legislate to suspend the institutions, the failure of power-sharing today is a very real prospect.
The police have said current members of the IRA were involved in the shooting of Mr McGuigan - in a suspected revenge attack for the murder of former IRA commander Gerard "Jock" Davison in Belfast three months earlier.
The revelations about the IRA has heaped pressure on Sinn Fein to explain why the supposedly defunct paramilitary organisation is still in existence.
The Ulster Unionists have already resigned from the Executive, claiming trust in Sinn Fein has been destroyed.
While the exit of one of the minor partners in the five party coalition did not bring a collapse, if the DUP follows suit the institutions will fall automatically.