On May 21, a selection of key seats will decide the political fortunes of the Coalition and Labor and the future of our country as a whole.

No single factor decides federal elections.

They’re always a crazy patchwork of local issues and national concerns, with demographic change, new candidates and parties and widespread voting trends keeping everyone on their toes.

As we head towards the May 21 election, 16 individual electorates are held on a margin of less than 3 per cent — a buffer that can be destroyed by one gaffe on the campaign trail.

Some of the usual ‘swing seats’ — Bass and Braddon in Tasmania, Gilmore and Eden-Monaro in NSW, and Longman in Queensland — are expected to pull focus once again, while the dominance of Labor in WA means seats like Pearce and Swan are widely regarded to be “in play” in 2022.

A massive ad spend by Clive Palmer could prove influential in a number of key battlegrounds, and the impact of One Nation, the Liberal Democrats and the Greens cannot be discounted.

Further complicating the picture this time around is the emergence of high-profile independent candidates challenging sitting moderate Liberals in seats such as Goldstein, Kooyong, North Sydney and Wentworth.

No results are known until the votes are counted, but these are the 29 seats that could decide whether the Coalition is returned for a fourth term, or whether Labor gets its first shot at power since the turbulent years of Kevin Rudd and Julia Gillard.

It was the bellwether seat for every federal election for more than 40 years, but since 2016 the southern NSW seat of Eden-Monaro has gone its own way. Former Bega Valley mayor Kristy McBain holds the seat on a wafer-thin margin of 0.8 per cent after winning a by-election in 2020 caused by the resignation of popular incumbent Mike Kelly. The Liberals have endorsed Pharmacy Guild executive Jerry Nockles.

Fiona Phillips won this Shoalhaven seat for Labor at the 2019 election but with a margin of just 2.6 per cent and lots of swinging voters, it will be seriously targeted by the Liberals, who have endorsed popular and high-profile former state MP Andrew Constance. Additionally, this year will not be a messy three-corner contest like it was in 2019, when the inclusion of a Nationals candidate split the vote. Labor is deeply worried about this seat and believe Mr Constance cancels out the negativity felt towards Prime Minister Scott Morrison over the bushfires in the region two years ago.

Craig Kelly first won this seat for the Liberals in 2010 but defected from the party after being criticised for his fringe views on Covid-19. He’s now backed by Clive Palmer’s United Australia Party as their star candidate, with a huge advertising campaign underway. The Liberals are hopeful of reclaiming the seat, and have endorsed planning and environmental lawyer Jenny Ware, the general counsel of Georges River Council.

Macquarie is Australia’s most marginal seat, with Labor’s Susan Templeman squeezing out a victory in 2019 on preferences. The seat’s historical volatility and the fact it’s held by a few hundred votes makes it one of a handful of seats the Coalition knows it needs to pick up in NSW, where the Liberal brand is strong. The Liberals have endorsed local councillor Sarah Richards.

Trent Zimmerman has held Joe Hockey’s former seat of North Sydney since 2015, but he has been targeted by the “Climate 200” group of independent candidates, who are targeting mainly moderate Liberals because of their perceived inability to push for stronger policies on climate change. While Zimmerman won convincingly in 2019, this year’s election looks set to be a genuine three-way contest, and the eventual winner could be decided by preferences. The Liberals believe Mr Zimmerman is under serious threat.

Veteran MP Julie Owens is retiring from this key western Sydney seat. She was considered a very effective local member with strong community ties so her departure give the Liberals a chance of clawing back the 3.5 per cent margin Labor holds it by. Labor has parachuted in former Kevin Rudd adviser Andrew Charlton from Sydney’s eastern suburbs — a move that riled local party members. The Liberals have endorsed the co-founder of Western Sydney Women, Maria Kovacic.

Labor has held this seat north of Newcastle the past two elections, but suffered a significant 5 per cent swing against the party in 2019 after alienating the mining and heavy industry-focused community. Prior to Meryl Swanson gaining the seat in 2016, it was held by the Liberals for 15 years, and the Coalition has indicated of all the three Hunter Valley seats, this is the one they believe is most likely to flip.

Reid was a Labor stronghold for decades before it was won by Craig Laundy for the Liberals in 2013. It’s been held by Fiona Martin in this parliamentary term but the 3.2 per cent margin makes it winnable for Labor, who believe they have a strong contender in Sally Sitou.

The Central Coast seat of Robertson has picked the winner of each federal election since 1983, and with a 4.2 per cent margin could switch back to Labor if there was a national swing. Labor’s local pick to help them achieve this is Dr Gordon Reid, a paramedic who worked on the frontlines during the pandemic, while the Liberals remain confident sitting member Lucy Wicks can hold on to the electorate.

Wentworth voted for independent candidate Kerryn Phelps in a 2018 by-election, its local constituents disgusted with the Liberal Party’s treatment of local member and former Prime Minister Malcolm Turnbull. Dave Sharma reclaimed the blue-ribbon seat for the Liberals in 2019, but Allegra Spender (daughter of deceased fashion designer Carla Zampatti) could be in with a chance if preferences from other candidates flow her way.

The main game in Victoria, this seat was held by Labor’s Anna Burke from 1998-2016, and the Opposition are a good chance to take it back. Julia Banks won it in 2016 but quit the Liberals in 2018 citing internal bullying. Gladys Liu won it by a margin of just .5 per in 2019 and will be targeted by opponents over her links to the United Front Works Department, the Chinese Communist Party’s international propaganda arm. Labor will throw a lot of money at academic Carina Garland’s campaign.

The retirement of former Speaker, Liberal Tony Smith — who has held the seat stretching from Melbourne’s urban fringe since 2001 — has given Labor an opening in Casey. Opposition strategists hope the emergence of Climate 200-backed candidate Claire Ferres Miles, the former boss of Sustainability Victoria, could cause havoc on preferences for the Liberal Party.

Always a tight seat, Libby Coker holds it by a margin of 1 per cent after wresting it from the Liberals in 2019. Labor believes the Covid-19 mass migration from Melbourne into the Surf Coast seat has made it more urban, and therefore safer. The Liberals have endorsed high-profile Geelong mayor Stephanie Asher and this will be a serious battle.

Liberal since its inception in 1984, Goldstein is nevertheless shaping up to be a battleground in the 2022 election. The challenge to sitting MP Tim Wilson will come from former journalist Zoe Daniel, running on a climate and integrity platform as one of the “Voices” candidates. While there are high-profile independent candidates running in a swathe of Liberal-held electorates, early polling suggests Goldstein could be one of the closer races.

A Liberal domain since 1945 (Robert Menzies and Andrew Peacock are former members), Kooyong has come into play in recent years. In 2019 Treasurer Josh Frydenberg saw off a strong campaign from human right advocate Julian Burnside for The Greens, but in 2022 the challenge will come from Professor Monique Ryan, one of the well-funded independent climate-focused candidates targeting most moderate Liberals. Expect serious money to be thrown at this campaign by both sides.

At first glance, Brisbane may not seem especially vulnerable for the Coalition — there are 13 seats on tighter margins — but recent reports of internal polling suggest Labor believes it will be very competitive in the seat. Climate, women’s issues and a national integrity commission are shaping up as key issues in the seat, which has been held by the Liberals since 2010.

Veteran MP Ken O’Dowd is retiring, giving Labor its strongest chance in years to seize this northern Queensland seat, which is on a margin of a deceptively-healthy 8.7 per cent. Labor has a very strong candidate in Gladstone mayor Matt Burnett, who is well-known and liked. The LNP also have a well-known candidate in local MP Colin Boyce, who is seeking to go from State parliament to Canberra. Seems likely on current polling the Coalition would retain the seat.

The economy in this tropical Queensland seat has been smashed by Covid lockouts, so expect jobs and economic recovery to be a key part of the campaign. Warren Entsch, who has held the seat since 1996, except for one term between 2007 and 2010, had been mulling retirement, but decided to contest the seat again to assist with the Covid recovery. Cairns-based union organiser Elida Faith is the Labor candidate again, after her failed tilt in 2019.

Held by Terry Young, elected in 2019 with a margin of 3.3 per cent, this is a perennial swing seat which tends to swing wildly. Young, who ran a golf franchise before being elected, is up against health policy expert Rebecca Fanning, who worked on the Queensland government’s Covid response. This is the Coalition’s most vulnerable seat in Queensland.

A Liberal Party stronghold since 1949, Boothby is in play this election after Liberal incumbent Nicolle Flint quit, citing vicious attacks against her by progressive lobby groups and unions. With a margin of 1.4 per cent, it will be a genuine battle between three strong female candidates — former St Vincent de Paul CEO Louise Miller Frost for Labor, healthcare consultant and Rhodes Scholar Rachel Swift for the Liberals, and the independent Jo Dyer, who gained a public profile in her advocacy for the now-deceased woman who made complaints against former AG Christian Porter, which he vehemently denied. Big swings against the Liberals were recorded in the areas covering this electorate in the recent SA state election.

Held by first-term MP James Stevens, Sturt was the long-term stronghold of former Liberal defence minister Christopher Pyne — he held the eastern Adelaide seat from 1993 to 2019. In a traditionally blue-ribbon area, Sturt has been put into play by a disastrous March 19 state election result for the Liberals, in which formerly blue-ribbon seats in Adelaide’s east were transformed into marginals.

While strong Labor sentiment in WA is expected to benefit Anne Aly in her fight to retain Cowan, it is by far the most marginal seat in the west. The abolition of the neighbouring seat of Stirling in a redistribution will pit sitting Liberal MP Vince Connelly against Aly in what could be a tough contest.

The seat held by the nation’s first indigenous Member of the House of Representatives, Ken Wyatt, since 2010 is considered to be in play. Although its margin is 5.9 per cent, it has a reasonably high number of swing voters, and Labor will strongly back its candidate, a former manager at mining giant Woodside, Tania Lawrence. It’s all about minimising losses for the Liberals in WA.

A Liberal domain since 1990, when the seat was created, Christian Porter won fairly comfortably in 2019, but his exit from federal politics means Pearce would be a prized target for Labor this time. The Labor candidate is Wanneroo mayor Tracey Roberts, while the Liberals have endorsed Linda Aitken, a clinical nurse specialist.

Western Australia is where Labor has a strong chance in several seats, and will be looking to leverage the popularity of Premier Mark McGowan. Long-term member Steve Irons has held the seat for 15 years — almost as long as Labor stalwart Kim Beazley in the 1980s and ’90s. The battle will be another between two female candidates — lobbyist and PR director Kristy McSweeney for the Liberals, and engineer Zaneta Mascarenhas for Labor.

A Northern Tasmanian seat based around the city of Launceston, Bass swings wildly: it has changed hands four times since 2004, and no MP has held it for more than a single term since then. The Coalition’s most marginal seat, it is held on a 0.4 per cent margin by Bridget Archer, who beat Ross Hart by just 563 votes in 2019. The wildcard is the impact and preference of Jacqui Lambie Network candidate Bob Salt.

A mainly rural seat in North-West Tasmania, Braddon has changed hands at every election since 2013, and was won by new member, former soldier and farmer Gavin Pearce in 2019. With a margin of 3.1 per cent and a reasonable number of swinging voters, it will be a key battleground. Labor has endorsed Burnie councillor Chris Lynch as its candidate. Senator Jacqui Lambie is from Braddon and the impact of her candidate, Sophie Lehman, could be important.

Tasmania’s largest electorate, taking in the state’s centre and east coast, Lyons has been held by Labor for all but one term (2013-2016) since 1993. The Liberals’ 2019 campaign was derailed when candidate Jessica Whelan was dumped over anti-Islamic social media posts, and the Coalition believes the strong support enjoyed by the State Liberal Government will help its candidate, local councillor Susie Bowers, this time around.

Labor’s Warren Snowden is retiring after holding the division (and its forerunner) since 1987, apart from a short break between 1996-98. A huge seat covering most of the NT, including the territories of Cocos (Keeling) Islands and Christmas Island, and numerous remote indigenous communities, it is almost impossible to poll. Labor has endorsed a senior indigenous woman in Northern Land Council CEO and former deputy chief minister Marion Scrymgour. The Country Liberal Party has endorsed the well-known former mayor of Alice Springs, Damien Ryan. A total wild card, will likely come down to personal votes.