With recent data on the economy suggesting higher than expected levels of consumer confidence, and opinion polls indicating that the Liberal-National opposition are still a long way behind in two-party support for the major parties, prime minister Kevin Rudd must be sorely tempted to go to an election sooner rather than later.

The Australian prime minister can consider a couple of ways in which early federal elections can be called. One way is for the prime minister to request an election from the Governor General.

The constitution dictates that parliaments may run for a maximum of three years, but there is no stipulated minimum time a parliament must run before a prime minister can ask for an early poll.

Having the parliament dissolved by the Governor General under the auspices of Section 57 of the Constitution is another way of bringing on an early election.

In this instance, a prime minister would need to have a parliamentary bill defeated in the Senate twice over a three month period before being in a position to inform the Governor General of the need to invoke Section 57.

In such a circumstance, both the House of Representatives and all of the Senate would be dissolved and all vacant positions would be up for election.

Section 57 has an additional, if rarely used mechanism.

If the government is returned at a double dissolution election, it may send the bill (or bills) that caused the election to be dealt with at a Joint Sitting of the parliament.

The government would expect to be able to get its legislation passed as its lower house majority would easily overwhelm the opposition numbers in the upper house.

All of this is very relevant to Mr Rudd as he prepares for the next parliamentary session at which his Emissions Trading Scheme (ETS) – the centrepiece of the government’s climate change policy – seems destined for defeat in the Senate.

A defeat for the ETS could thus become the trigger for the commencement of the double dissolution process.

Would Mr Rudd consider a double dissolution election?

One of the dangers of an election occurring for all of the Senate (instead of the usual half-Senate election) is that the share of the vote needed by political parties to win a seat in the upper house falls to a little less than 8 percent.

This greatly increases the chance of a minor party of winning a Senate seat.

Given that Mr Rudd has had a lot of difficulty with minor parties such as the Greens and especially Family First in his dealings with the Senate thus far, it seems unlikely that the prime minister would want to do anything that might enhance their chances of being returned or increasing their numbers.

Were Mr Rudd to allow for a normal half-Senate election, some of the problems he has had with the Senate would be resolved anyway.

The next half-Senate election would see those senators elected in 2004 defending their seats, and it seems highly unlikely that Family First’s Steve Fielding would be returned.

The Liberals would also lose at least one seat in Queensland where, in 2004, they needed Pauline Hanson’s preferences to win their third seat.

The only reason why Mr Rudd would go to a double dissolution would be to utilise the Joint Sitting mechanism to get his ETS program through the parliament without any amendments demanded by either the Liberals or the Greens.

An early election should still be expected, but whether or not this will be a double dissolution election will depend entirely on how committed Mr Rudd is to a government-designed ETS free from alteration at the hands of the opposition parties.