It can happen in an instant, that moment when a party or politician’s fortunes changes direction.

It’s usually unexpected, at least to the voting public, and almost impossible to turn around.

Some are external, like the September 11 attacks that helped Liberal PM John Howard win the 2001 federal election.

Others are self-inflicted, like the “birthday cake gaffe” that helped another Liberal leader, John Hewson, lose in 1993.

And then there are the game-changing election campaign events that are created by one’s political enemies, such as this week’s emergence of a video that showed NSW Labor leader Michael Daley claiming young people were being forced to leave Sydney because foreigners, typically from Asia, were taking their jobs.

NSW Opposition Leader Michael Daley addresses the media outside Allianz Stadium in Sydney. Photo: AAP

We’ll know soon enough whether Mr Daley’s comments helped to bring about his defeat at this weekend’s state election in NSW.

Before the leaking of that video and his stumble during a televised debate with the Liberal Premier, Gladys Berejiklian, opinion polls had suggested the Labor opposition had drawn level with the Government.

At the national level, our Prime Minister, Scott Morrison, also faced a couple of potentially game-changing events in in the past week.

NSW Premier Gladys Berejiklian (left) and Prime Minister Scott Morrison during an Interfaith gathering for victims of the Christchurch terror in Sydney. Photo: AAP

The horrendous attack in Christchurch, New Zealand, could have been one of those tragic moments when communities lean towards their incumbent government rather than the alternative.

Tony Abbott’s government benefited in this way after the downing of commercial airliner MH17, as did John Howard’s after the Port Arthur massacre.

The Christchurch killings are different, however, in a way that is likely to worsen the PM’s already diabolically bad political fortunes.

Australian voters have been shaken by the knowledge that the gunman is one of us – not an un-relatable madman like the Port Arthur shooter, but a man whose extreme views against non-whites, and particularly Muslims, did not stand out because our society has begun to normalise – and in some cases promote – such views.

It’s likely many voters have been forced to confront their own prejudices in light of this event, and reassess their views about the likely perpetrators of extremist violence and terrorism.

Such soul-searching has made voters scared and angry, lashing out at those who seemingly refuse to accept that a tipping point has been reached where xenophobia, prejudice and racism will no longer be ignored or deflected but actively challenged and rejected.

As a result, the tragedy in Christchurch has become a negative for the Prime Minister, specifically, and the Coalition more broadly.

Many Coalition MPs and their boosters in the media have been blind in the past to shifts in the Australian community’s views on marriage equality, kids in offshore detention and climate action.

Liberal seats have been lost as a result, in last year’s Victorian state election as well as at the national level in the Wentworth by-election.

More Liberal seats are likely to fall for the same reason when voters go to the general election in mid-May.

It’s clear that the Christchurch massacre has set off another seismic shift in voter views, this time raising resistance against those who promote, foster or propagate hate speech against Muslims.

Prime Minister Scott Morrison addresses media at Lakemba Mosque. Photo: AAP

This changing environment cast a new light this week on an old accusation (leaked to the media by fellow Cabinet ministers) that Mr Morrisonm as the minister for immigration, sought to exploit voter concerns about Muslim immigrants.

The PM did the best he could to minimise the damage by participating in a live, 30-minute interview with one of the journalists who reminded voters about the allegation this week.

Prime Minister Scott Morrison with Waleed Aly on Thursday. Photo: Channel Ten

It’s now undisputed that Mr Morrison did raise the issue of Muslim immigrants at the time, but there’s no way to prove whether he or his anonymous accusers are telling the truth about his reasons for doing so.

Much more problematic for the PM is the question of how the Coalition parties will preference One Nation at the upcoming general election.

The Opposition has performed an excruciating wedge on Mr Morrison by demanding that the Coalition follow Labor’s lead and place One Nation – a party that openly demonises Muslims and their faith – last on Liberal and National how-to-vote (HTV) cards.

Labor doesn’t rely on One Nation preferences, so this is an easy sacrifice, whereas the Coalition parties do.

What’s more, Coalition MPs fighting in very marginal seats may lose if One Nation’s leader, Pauline Hanson, decides to retaliate by placing them last on her party’s HTV card.

Pauline Hanson makes no secret of her disdain for Islam. Photo: AAP

Unlike the Coalition, Labor has detected this shift in voter sentiment and made the preferencing of One Nation a matter of moral integrity.

Anything less than a blanket decision to preference One Nation last will be depicted as collusion with hate-preachers.

Meanwhile, the industrial arm of the Labor movement, the ACTU, is running a campaign that urges voters to ‘put Liberals last’ (rather than One Nation) in the general election, arguing that it’s focusing on the candidates that can actually win seats.

Scott Morrison should try arguing the same.

The logical extension of the moral challenge issued by Labor to the Morrison Government is that no succour should be given to those who promote, foster or preach prejudice against Muslims.

Surely this should include Sky News Australia, which has not only provided a platform for hate preachers, but whose late-night commentators habitually demonise Muslims, immigrants and asylum seekers.

Andrew Bolt is a member of Sky News’ opinionated lineup. Photo: Sky News

By removing all current and former Labor and Labor-aligned interviewees, panelists and hosts from Sky News programs, Labor would demonstrate that its One Nation preferencing challenge to the Coalition is more than a cheap wedge.

What’s more, a pre-election ban on Sky News appearances by all parties would send a signal to Australian voters that our calls for an end to hate speech against Muslims had been heard.

Now THAT would be a demonstration of moral integrity.