Extending voting rights brings own problems
It beggars belief that Martin McGuinness of Sinn Féin was allowed to run as an Irish presidential candidate and at the same time could not cast a vote in the election that he was a candidate in.
All electoral systems say — if you cannot vote, you cannot run. This has spurred on the current situation that wants to give Northern politicians, especially Irish, a bigger vote than they would get. Article 3 of the Irish Constitution is not unlike the old Article 3 before 1998 in wanting a unitary state.