The reason is that these people are involved not in illegal activity but in electioneering, seeking seats in the new Belfast assembly whose 108 members will be elected tomorrow.
The Irish peace process means that the assembly will bring together not only conventional politicians but also republicans and loyalists whose previous paramilitary activities led them to long stretches behind bars.
The phenomenon of prisoner-turned-politician is a familiar one in Irish history, and is often regarded not as a disgrace but as a badge of honour. The 1960s terms served by the Rev Ian Paisley were recently commemorated in a new stained-glass window in his Martyrs' Memorial Church.
Gerry Adams and Martin McGuinness, of Sinn Fein, are already MPs, while a number of their Unionist counterparts have also been to jail following protests against the Anglo-Irish agreement. Mr Paisley's deputy, Peter Robinson, spent some time in prison in the south for a nocturnal incursion across the border.
Perhaps 20 republican and loyalist assembly candidates have been to prison, with Sinn Fein members making up most of these. Republicans have regularly elected ex-prisoners; in 1981 they elected to Westminster Bobby Sands, the IRA prisoner who was at the time on hunger strike in the Maze.
In recent years, Protestants have shown a greater willingness to follow suit, as can be seen in the rise of parties such as the PUP and UDP, which grew out of paramilitary groups. Figures such as David Ervine and Billy Hutchinson are already Belfast councillors, and stand a good chance of election to the assembly.
What is unusual is that many Catholics say they intend to vote for such loyalist candidates, saying they approve of their transition from the paramilitary to the political.
But for many the idea of transformation is no less difficult and painful because the path is a familiar one. The killings carried out by John White of the UDP took place a quarter of a century ago - 25 years to the day, in fact, before tomorrow's election.
But the fact the victims were stabbed dozens of times means the killings are remembered as being among the most brutal of the troubles. Two years ago, when John White met John Major, the son of one of those killed said: "When I look at White's face I think about the screams of pain he must have listened to. The screams must haunt [him], mustn't they?"
In a rejoinder, Mr White wrote: "I can fully understand the hurt and anger felt towards me. It is natural and I accept it.
"I do not ask him for forgiveness for his father's death, merely for recognition of the fact that my life is now devoted to trying to avoid further suffering ... it is often those who have been closest to the conflict who become the most constructive forces. Such positive contribution should not be inhibited; it should be encouraged."
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