This principle was easier to believe when all MPs had their own electorate; they would not have won it without their party identity but at least they represented something besides a political organisation. The adoption of proportional representation has written parties into electoral law, put them at the centre of the system and let them fill list seats with no reference to a wider electorate.
They can bring whomever they want into the House but once they put people there, and the clerk of the House swears them in, the party should not have the power to evict them. The better procedure would be - and this would seem particularly proper in Mr Horan's case - that the party must apply to the Speaker of the House to have the MP removed.
That would bring a more independent judgment to bear on a case of alleged conduct unbecoming a member of Parliament. It would avoid the risk that the member's leader and party are taking precipitate action for their own political purposes rather than giving the member a fair hearing.
Mr Horan's lawyer, Paul Mabey, QC, said he had not been shown the information Mr Peters has received and believed, and had not been given an opportunity to reply to it. Others have noted that the allegations against Mr Horan posed particular problems for NZ First because the party finds the core of its support among the elderly.
By acting quickly, Mr Peters has probably minimised any damage to the party and there can be little sympathy for Mr Horan on the basis of what was said in his mother's will. Nor can there be much sympathy for him over his summary dismissal from NZ First. He put his name on that party's list knowing the party is Mr Peters' creation and remains more beholden to its leader than any party the country has seen.
If Mr Horan has nothing to offer the public in answer to a family member's allegations he ought to resign from Parliament. If he does not, there is little that can be done about it under the House's rules. It would be better and fairer if someone could adjudicate.