For the second time in a week, it was a good election for the opinion pollsters. New Zealanders on Saturday voted very much as they’d said they would, putting the opposition National Party in office by a clear margin. John Key, who is almost exactly the same age as Barack Obama (according to Wikipedia, they were born five days apart), will be the new prime minister.

The latest figures show National with 59 seats, or 65 counting its supporters ACT (with 5) and United Future (1). Labour and its allies have 52, and the Maori Party five. Postal and absentee votes have yet to be counted, but it’s unlikely those totals will change, although the Greens (currently on 8) may pick up a seat at the expense of National.

The National Party had 41.5% of the vote, which in most English-speaking countries would give it a solid majority in its own right. Going by just the single-member electorate seats, National won 41 out of 70 (preferential voting might change that slightly, but not much). But New Zealand’s Mixed Member Proportional (MMP) system reins in such lopsided results and usually obliges the major parties to rely on allies.

Despite proportional representation, however, New Zealand has failed to develop a real multi-party system. The two major parties have almost 80% of the vote between them, and that proportion has generally been increasing – up from 62.4% in the first MMP election in 1996 (Adam Carr has the figures). Electoral systems matter, but clearly they don’t determine the shape of the party system on their own.

Moreover, the minor parties have been losing their freedom of movement: most of them are now locked in behind one major party or the other. Winston Peters’s New Zealand First, which had shuffled unpredictably between the two, has been eliminated from parliament (Peters failed to win an electorate seat, and his party fell below the 5% threshold), leaving the Maori Party as the only real independent force.

New Zealand seems to be moving in the same direction as Italy, where voters in effect choose between two broad coalitions, but also determine the balance of power within the coalitions.

In putting together a government, Key will have to decide how much ground he is willing to give to his allies. So far he has indicated a moderate course, reaching out to the Maori Party and refusing to offer a ministry to ACT’s Roger Douglas, the former Labour deputy PM and radical free market reformer.

In the 1980s, Douglas’s reforms were just what New Zealand needed, but now its voters seem content with the middle ground that Labour and National both occupy.