RODNEY HIDE: Nine seats? Try four

Rawiri Waititi was in fine form arriving at Parliament this morning. "If you look at our five seats plus the four overhangs, that's nine seats we've delivered to making sure this is a one-term government," he said.

Nine seats. It's a neat trick. The Māori Party won five electorates. Four of those five are overhang seats. The four overhangs are four of the five. Count them twice and you get nine.

There has been a lot of nonsense spoken about the overhang since the election. Most of it is wrong. And most of it is spoken out of political self-interest. Mr Waititi is the best example but he is far from alone. Chris Bishop, having lost his seat, has suddenly discovered that MMP is bad for democracy.

So let's do the sums properly. The figures are from the preliminary count. The specials are still to come and will shift a seat or two.

First, what happened. National won 42 electorates on 29.2 percent of the party vote. That entitles it to 35 seats, so it has seven overhang seats. The Māori Party won five electorates on 0.6 percent of the party vote. That entitles it to one seat, so it has four overhang seats. Eleven overhang seats make a House of 131. It takes 66 to govern. National, ACT and New Zealand First have 67.

Now suppose there was no National overhang. Suppose the National voters who gave their party vote to ACT and New Zealand First had kept it with National instead. It would take about 124,000 party votes staying with National for its party vote to match its 42 electorates. National would be on 34.6 percent, ACT on 8.3 and New Zealand First on 7.4.

Here is the result. National 42 seats, with no overhang. ACT drops from 13 to 10. New Zealand First drops from 12 to 9. Labour drops from 36 to 35. The House is 124 and it takes 63 to govern. National, ACT and New Zealand First would have 61. No majority. Labour, the Greens and the Māori Party would have 56, and Opportunity, with seven, would decide who governs.

That's the point the pundits have missed. The split vote didn't cost the centre-right. It won them the election. Those 124,000 votes were worth six seats spread across ACT and New Zealand First. Keep them with National and the government loses its majority. The National grandees who told voters splitting was stupid were wrong. RCR's pamphlets and ads told voters to split their vote, and they were right.

Now take it one step further. Keep National with no overhang, and suppose the Māori Party had no overhang either. For its party vote to match its five electorates, the Māori Party needs about 90,000 party votes, roughly 3.8 percent, against the 13,845 it actually got. Mr Waititi's strategy was for his voters to give their party vote elsewhere, so suppose the extra 76,000 come back from the Greens.

Here is that result. The House is 120, the size MMP intends, and it takes 61 to govern. National 42, ACT 10 and New Zealand First 9 make 61. A majority, just. Labour 35, the Greens 12 and the Māori Party 5 make 52. Opportunity has 7.

So what did Mr Waititi deliver? Not nine seats. On the same arithmetic, his voters' party votes lifted the Greens from 12 seats to 16. He delivered four seats, and they were Green seats. And they didn't stop the government. The centre-right's split was worth more than his.

And note: no overhang -- and still Mr Bishop loses his seat.

Rodney Hide is a former minister and ACT Party leader