Not unless republicans/nationalists win a majority in an election it doesn't."
As part of the Good Friday Agreement, an explicit provision for holding a Northern Ireland border poll was made in UK law. The Northern Ireland Act 1998 states that “if at any time it appears likely to him that a majority of those voting would express a wish that Northern Ireland should cease to be part of the United Kingdom and form part of a united Ireland”, the Secretary of State shall make an Order in Council enabling a border poll.
It is not clear exactly what would satisfy this requirement. The Constitution Unit suggests that a consistent majority in opinion polls, a Catholic majority in a census, a nationalist majority in the Northern Ireland Assembly, or a vote by a majority in the Assembly could all be considered evidence of majority support for a united Ireland.
The criteria has been set for the border poll. If their is a no deal brexit then a vote on the matter will have to be called.
No counting Alliance and Greens.
Come back to us when that happens.