Nigel Dodds has pronounced the IRA defeated – but pledged to fight "a political battle" against republican and nationalist influence on such issues as flags, parading and the definition of victims.
He said their "claims that there would be a united Ireland by 2016 have as much credibility as Basil McCrea suggesting he will be the next First Minister".
He pointed to recent opinion poll data and the fact that only 25% of people in the most recent census gave their nationality as Irish.
"The IRA has been defeated. They tried to bomb us into a united Ireland and we stood firm. They tried to wreak havoc in the rest of the United Kingdom and further afield, hoping their campaign of terror would cause the resolve of the British people to waver. But we stood firm," he told delegates to applause.
He congratulated his party on its achievement.
"Northern Ireland's constitutional position has never been more certain and secure than it is today," he said.
"Republicanism has failed. Nationalism is struggling to keep the notion of a united Ireland on the political agenda. The IRA has been defeated... people in Sinn Fein try to pretend that their project of a united Ireland is still on track.
"But they are failures and they know they are failures."
Despite these successes for the unionist cause, he warned of dangers ahead and called for unity behind the DUP banner in next May's councils and European elections. His wife Diane (below) is the DUP's sitting candidate in the European poll. He said she "has made it her goal to work hard, to deliver tangible benefits for Northern Ireland in the parliament and here at home. And there is no doubt that she has delivered on all of these objectives".
He told the conference to remain wary of Sinn Fein.
"The political battle against republicanism must still be fought. They haven't gone away. In an attempt to distract their own followers from the scale of their failure, Sinn Fein have embarked on a strategy to whip up problems on our streets over cultural and other issues," he added.
He pledged that his party would resist and would champion the cause of victims, a key constituency identified by DUP election planners.
"As a party of justice we will not stand by while others attempt to equate those who perpetrate violence with the innocent people who suffered at their hands. That is not justice," the North Belfast MP said.
He added that his Westminster colleague Jeffrey Donaldson was promoting a Private Member's Bill "to change the definition of a victim so that those who died or were injured as a result of their own terrorist actions or if they have a conviction for terrorist-related activity would not be considered victims".
The conference continues today.