The pro MMP poster at No Right Turn says I’d rather live in a democracy with 120 MPs than a dictatorship with 99.
I’ll ignore the debate on whether MMP really is any more democratic than other electoral systems and stick with the numbers.
If we still had FPP we wouldn’t yet have 120 MPs but we’d have more than 99 unless the formula for setting electoral boundaries had changed.
The number of electorate seats keeps increasing under MMP and they would have under FPP too.
The number of South Island seats was fixed under FPP and still is with MMP. Under both systems the South Island population is divided by that fixed number of seats and that figure is used to determine how many people will be in each electorate in both islands, plus or minus 5%.
The North Island population grows faster than that of the South so every six years when electorate boundaries are calculated we get another seat or two.
Had we still had FPP we’d be approaching 110 MPs.
This formula is why MMP will eventually stop working as it’s intended to. Each time an electorate seat is added a list seat is subtracted. We started with 65 electorate seats (60 general and 5 Maori) and 55 list seats in 1996. Now there are 70 electorate and 52 list seats (an overhang of two).
Unless there’s an increase in the total number of seats in parliament we’ll get to a stage where the number of list seats is so small proportionality will be lost.
The alternative is to reduce the number of South Island electorates but the big rural electorates in both islands already cover far too big an area.
Whatever the referendum result, there will have to be changes eventually and the price of maintaining proportionality might be more MPs – electorate and list.