NSW is the biggest democratic jurisdiction in the country. It has been shaped by an unprecedented housing boom that has transformed Sydney, its capital city, both socially and politically. So, what does it all mean for a battle-weary Liberal government fighting for its life, against an energised Labor opposition looking to form government?

The last time NSW Labor won a state election, the median three-bedroom house price was just under $500,000, and at the top end, about 10 times the annual median income of a Sydney resident. Today, nearly 16 years later, you will not get much change out of $1 million and for many Sydney residents, they are sitting on mortgages that are 15 times their annual income.

The seats currently held by NSW Labor embody all of the most favourable demographic characteristics they could wish for, once you venture into seats like Oatley, Winston Hills and even the ultra-marginal seat of East Hills, the demographic landscape for Labor is riddled with potholes and obstacles.

These potholes and obstacles are specific to Sydney and to a lesser extent, NSW. They are not present in my state Victoria. Unlike Victoria, Labor in NSW cannot simply rely on the Millennial demographic wave.

In Melbourne, highly educated millennial progressives can still live in many of that city’s inner suburbs, even though housing attainment has also recently reached crisis levels. Poorer migrants have, over the last decade, been able to access the property market along Melbourne’s growth corridors, creating vast stretches of political territory friendlier to the left side of politics. The growth of favourable political territory was not hindered by Melbourne’s property market. Just before the pandemic, a low-income migrant family was still able to purchase a home along Melbourne’s outer fringes.

Sydney’s Labor seats have become magnets for struggling migrants and educated millennials without assets. Unfortunately, skyrocketing property prices have made it nearly impossible for them to venture beyond the city’s outer western suburbs. This has led to a shift in Sydney’s political landscape, with these vital cohorts being funnelled in existing Labor strongholds. As a result, the party now holds a majority of seats with the highest number of renters and the greatest diversity.

Parramatta is a massive exception to this, containing the highest number of renters out of any NSW state seat. Our recent polling suggests that this, coupled with high levels of diversity has opened up a large gate for Labor to pass through and secure the seat.

This gate closes as we head further out to seats like Penrith. It has fewer renters, it is less diverse and it is certainly not the seat that Labor once used to hold at the turn of the 20th century. Based on our research, the Liberal Party is still hanging on, but only just. One of their biggest threats is One Nation, who seem to be cannibalising votes on the Liberal Party’s right flank. Unlike other states, the Liberal Party cannot rely on preferences to secure this loss. In 2019, only 25 per cent of One Nation voters did not exhaust their vote in Penrith. Of that, only 14 per cent ended up flowing back to the Liberal Party.

We expect this pattern to repeat itself right across Sydney. Labor’s path will be made easier where seats contain a greater number of renters and poorer voters from diverse backgrounds. That results in a limited number of seats which present real opportunity for Labor (including Parramatta and Ryde), but that key demographic trend is not as strong in other critical seats like East Hills.

Although political gravity alone may indeed cost the Coalition enough seats to oust them from government, the demographics of Sydney matter more than any other political landscape in this country.

I have focused mainly on Sydney because outside NSW’s capital city, there are few options for Labor growth. Throw into this mix an optional preferential system and the contest will indeed be a seat-by-seat tussle. In several seats, the Liberal Party may indeed get into trouble because they bleed too many votes to their right flank, mainly to parties like One Nation. On the flip side, Labor can to a certain extent afford to bleed a little to the Greens as exhaustion rates amongst Greens voters is always much lower.

If the combined major party vote ends up at historical low levels (as we have seen in other recent political contests), the optional preferential system will ensure a very long night for many who are following this election.

Kosmos Samaras is a pollster and the former Deputy Director for the ALP and is the Director of Strategy and Analytics for the Redbridge Group, he comments regularly on politics for major news outlets. www.redbridgegroup.com.au