The ritual denials were all there from the treasurer and his colleagues, but of course this budget is primarily a political document.

It is designed to buy voter support: not just at the election, but perhaps even more importantly in the next few weeks’ opinion polls.

Without some sort of “bounce”, the government risks being written off before the campaign has even begun. But a 15-point lead doesn’t just evaporate on its own. The government needs something big, and the budget was supposed to be its best chance to get it.

So who is it targeting? Where does it hope to find the votes it needs?

The usual suspects are all there, as they have been through the Howard government’s tenure: the old folks, families with children, the rich, and of course the military. But this year the money seems to be spread around pretty widely; less well-off young single people in the cities might not get their fair share, but they won’t come away empty handed.

Presumably the government feels that more specific targeting can wait until later in the year: what it needs now is a general impression of overwhelming largesse, to try to shake loose some swinging voters wherever they may be found.

For some ideas on who the key groups are, its interesting to look at this week’s other big story – the French presidential election. An Ipsos exit poll (story in English; full report in French) reported the vote received by the centre-right’s president-elect Nicolas Sarkozy among different age groups:

18-24: 42%

25-34: 57%

35-44: 50%

45-59: 45%

60-69: 61%

70+: 68%

So the left’s strength is with the youngest voters, and also with their parents, the baby boomers. The right is supported more by older voters, but also has a spike in support from Gen X, currently in their 30s.

For historical reasons, we don’t have detailed exit polling in Australia, but what we know about Australian electoral behavior suggests that the pattern in very similar. John Howard’s victories have depended heavily on the over-60s; he gets very little joy from new voters, which is why his new electoral legislation is designed to prevent many of them from voting.

To win again, the government needs to somehow broaden its appeal. Last night’s budget could be the first step towards doing that, but there’s a long way to go.