Consensus has it that next month’s Victorian election is going to be close, with some speculation that if the Greens win a couple of seats they could end up with the balance of power. So it’s surprising that so little attention is being given to the fact that at the last election an even smaller party actually did so.

That was, of course, the National Party, which in 2010 won 10 seats for its 6.7% of the vote (the Greens had 11.2%), making it — at least in theory — the kingmaker between the Liberals, on 35 seats, and Labor on 43.

Of course, the balance of power was theoretical rather than real. The Nationals were committed beforehand in a coalition with the Liberals, and there was never any doubt that they would work together. But readers in other states might not appreciate how unusual that situation is in Victoria.

North of the Murray, a coalition between the two non-Labor parties has always been the norm. It would be wrong to say that relations have always been harmonious, but most of the time they have managed to co-operate reasonably well. Historically, Labor was so strong in New South Wales and Queensland (and in Western Australia as well) that its opponents knew that their only chance was to work together.

But for many decades, Labor in Victoria was much weaker. The other states all had successful Labor governments in the early part of last century, but Victorian Labor didn’t win a majority in its own right until 1952 — and even then it destroyed itself in the split, putting itself out of office for another 27 years.

The result was that the Liberals and Nationals (formerly the Country Party) could afford to spend much of their time fighting each other, and they did. The National Party developed into quite a different beast from its interstate counterparts, adopting more left-wing positions and often co-operating with Labor — which in turn, of course, enjoyed exacerbating the differences on the other side.

When Jeff Kennett formed a Coalition government in 1992, it was the first time the Nationals had been in government for 40 years, and even then it was something of an act of charity — the Liberals held a majority in their own right. Only in 2010 did the Nationals return to the balance-of-power position they had lost in 1952.

By then, however, relations with the Liberals had been patched up. After the 2006 election, then-opposition leader Ted Baillieu set himself to forging a coalition deal. He offered generous terms, including a Senate seat that the Nationals would have been unable to win on their own, and the Nationals signed up.

The deal worked for the Liberals: it won them government without having to fend off questions about a hung parliament. And it worked in spades for the Nationals, who scored their best result (at least in seats) since the 1980s.

Their underlying level of voter support is harder to assess. The Coalition agreement means that very few voters are given a choice between Liberal and National candidates, so their total vote is a somewhat arbitrary figure. It may be significant that Newspoll consistently puts the Nationals at only 3% or 4%.

Nonetheless, at the last two elections the Nationals have been generally gaining on the Liberals in their three-cornered contests, picking up Mildura and Morwell in 2006 and Gippsland East in 2010. This year they will making a serious effort in Eildon and Ripon, two nominally Liberal seats changed by redistribution.

Whatever the result there, if the government is returned the Nationals will again expect to have it both ways: being treated as a loyal partner who would never defect to the other side, but also getting the weight in government that befits a genuine balance-of-power holder.

And the Liberals, as before, will play along with the charade.