The Northern Secretary, Mr Peter Mandelson, has urged unionists to "put aside the fear of failure" and accept the decommissioning and devolution deal.
If the Mitchell review package was rejected tomorrow, the future opportunities for their generation would be lost, he told Belfast sixth-formers.
He repeated his conviction that the IRA would decommission. He held this view because Mr Gerry Adams and Mr Martin McGuinness were realistic politicians who genuinely wanted this political peace process to succeed. But if it did not happen the British and Irish governments would suspend the institutions of the Belfast Agreement.
Mr Mandelson travelled to Victoria College in south Belfast yesterday to deliver his final keynote speech of this short campaign for Ulster Unionist Council (UUC) votes. This was a "defining moment" for the UUC, he told students from Victoria, St Malachy's and Dominican colleges in Belfast. "Next week direct rule could end. Next week Northern Ireland could be standing on its own two feet, ready to walk, with its head held high, into the future," he said.
"That is why I passionately hope that the Ulster Unionist Council will decide to break the deadlock and take the next decisive step forward, knowing that there is a lot to gain but that if the process fails they will be no worse off.
"If they do not say Yes, no one should be under any illusion about the dangers that will lie ahead. The opportunity of a generation - your generation - would be lost. Whatever else we got we would certainly not get decommissioning. There would be no guns and no government," he added.
"My message to unionists today is this: put aside the fear of failure. Present the face of progressive, tolerant, confident union ism. A unionism that reaches beyond the politics of `Not an Inch', a unionism that is justifiably proud of its traditions, including its Orange ones, and knows they can flourish alongside the expression of Gaelic ones. A unionism that is on the front foot and comfortable in its co-existence with those who hold a democratic nationalist aspiration."
Mr Mandelson said he believed IRA decommissioning would take place for two reasons. "The first is that Gerry Adams and Martin McGuinness are, like David Trimble, forward-looking politicians who - whatever their pasts - have staked their reputations and their futures on making this process work.
"I believe they will use their influence, and I believe they will use it successfully."
Mr Mandelson continued: "The second is that they are also realists. They know that Gen de Chastelain [who heads the decommissioning body] is a man of complete integrity who will not be put off by prevarication, or pretend that black is white. He will tell it as it is no matter what.
"They also know that if there is default on decommissioning they will be diminished in the eyes of world opinion. A great many people will be disappointed. We and the Irish Government will act together, without delay, to suspend the institutions.
"There is therefore no way that anyone could profit from default on decommissioning, or indeed on devolution, since the other side of the bargain is that devolved government will be established and implemented in good faith."