List MPs, such as Mr Horan, are not elected by the people to represent them in their electorate. They enter Parliament on the party vote.
Prime Minister John Key last year said he supported moves to empower the removal of list MPs such as Mr Horan before saying it could require a law change and was not a high priority.
Then, this week, New Zealand First resurrected the debate by announcing a rule had been written into its constitution that its MPs who had been sacked or resigned from the party could face a $300,000 fine if they did not give up their seat within three days.
Legal experts are already saying the change is unlikely to be enforceable.
Mr Horan told the Bay of Plenty Times the rule was laughable.
"If [an MP] wants to vote against the party they will be sacked. It is completely against democracy," he said.
Mr Horan has a point. The rule change could stifle freedom of expression within the party's ranks.
MPs might be reluctant to express alternate views or disagree with the party leader if such a rule was in place.
NZ First created much of this mess by expelling Mr Horan so quickly.
If Mr Peters had instead stood him down until the matter was resolved, this issue may not have arisen.
But Mr Horan has to accept he was not elected as an independent MP and on that basis does not have the mandate to remain in Parliament at great cost to the taxpayer.
His fate will be decided by voters this year but - regardless of the result - the Government needs to address the complex questions this saga has raised in relation to our political system.
