Is it a prize for ACT voters? For Bill Shorten and the Australian Labor Party? Or is it a prize for a small handful of careerists who see themselves in the running to win the seat? Perhaps the best answer is that it's a prize for all three.

Furthermore, is it a largely symbolic prize or one with significant practical import? The symbolic value depends on where you sit. For those Canberrans inclined to be complacent or dismissive about this latest development, first consider the reaction of voters in South Australia, which has yet again lost a seat, its number now falling from 11 to 10 (the lowest number of SA seats since 1954).

South Australians see the trend as catastrophic, an indication in the words of the Minister for Defence Industry, Christopher Pyne, that "we are in decline as a state". Predictably, he blamed the state Labor government. The SA Property Council declared the development was "hurting our national level of political influence". Pyne pointed out that whereas in 1999 both Western Australia and SA had 13 seats, from the next election WA would have 16 and SA 10.

Amid the partisan politics about the "ruthless arithmetic of politics", SA Premier Jay Weatherill said the state's recent positive record of influence in national politics (it must be said through the Nick Xenophon Team party in large part) showed that the quality of argument and the strength of advocacy matters more. He pointed to national policies on submarines and the Murray River. That response shows a touching belief in rational political processes for a hard-headed politician, but does offer an alternative perspective for Canberrans.

How good is a third seat going to be for ACT voters? Quite a lot if you can agree that MPs perform a useful function (not everyone does agree about this, with general trust in Australian politicians at a low ebb).

Going from two to three (and four to five in the whole Parliament) is a much bigger percentage change for the ACT than either the loss for SA or the percentage gain for Victoria's representation, which is growing from 37 to 38 seats.

A third seat means a 50 per cent increase in the number of members of the House to serve ACT constituents' needs and an equivalent increase in the number of electorate staff who do much of the grunt work. This should mean that our two hard-working MPs, who serve the largest electorates by population in the country, should be much more accessible.

Not everyone wants to engage with their local MP so for many people that will make no difference. They may have a point. The 50 per cent increase is comparable to the recent increase in the size of the ACT Legislative Assembly. Can it be shown that MLAs are more accessible in the new Assembly? I haven't seen the hard evidence.

Nevertheless, the third seat should mean more "doctor's surgeries" by MPs, more visits by MPs to local shopping centres, quicker responses to letters, emails and inqueries, and so on. More should make a difference, at least numerically, no matter how hard individuals work.

The second benefit for the ACT should come from a louder ACT voice within the party room of the successful party. There seems to be universal agreement that Labor will be the likely beneficiary. The ACT Labor party room contingent will be increased from three to four overall.

But let's be realistic. That party room is divided by faction, which is a powerful force in internal deliberations. Territorial representation has only limited impact by comparison. The big factional groups come from the bigger states and they are the ones who throw their weight around on matters such as contentious policies, campaign tactics and leadership selection.

Furthermore, the ACT voice has always struggled because of a negative, Australia-wide view of us as an isolated enclave of privilege. We are not taken seriously within the major political parties.

National party politics puts a different perspective entirely on a new seat for the ACT. If it just means an extra Labor seat, then the 40 per cent of Canberrans who don't vote Labor may have a different view. The new seat may even be the difference between the return of the Coalition government and the election of the Labor opposition. If asked to choose between a better deal for their territory and a better deal for their party, most Coalition voters may choose party. The same would be true for Labor voters in similar circumstances.

The new seat won't mean much if it just becomes an arena for the narrow world of party politics. Factional heavies will want to pull rank and it may take a local rebellion to clear the way, as happened when Gai Brodtmann and Andrew Leigh were first preselected in 2010.

My wish is that the big prize attracts a big field of heavyweight candidates. I don't mean heavyweight measured in party terms but in having the skills, life experience and concern for the common good to become Australian leaders. They are the candidates that a privileged and progressive community like the ACT should always produce. It has done so in the past when preselection contests have attracted some of the best and brightest from the community and public sectors, and it must do so again. The ACT community will be tested to prove its worth.

John Warhurst is an emeritus professor of political science at the Australian National University.