It is easy to identify the problem; finding the right solution is another matter altogether.
That is how the Prime Minister yesterday summed up the frustration of many MPs that a list member could be expelled from his caucus yet stubbornly still remain in Parliament as an independent MP.
John Key is right. There is general agreement across Parliament that - presuming Winston Peters is justified in dumping Brendan Horan - the latter should resign from Parliament.
One answer is to resurrect the long-expired law stopping MPs from jumping ship to other parties. The so-called "waka jumping" legislation passed by the Labour-Alliance coalition in 2001 did its job. But it had a "sunset clause" and expired in 2005.
On the urging of NZ First, Labour tried to revive the law late that year. But the measure eventually foundered for lack of numbers. National and the Greens opposed it.