The attempted assassination of a former US president should teach Australian politicians a lesson about the consequences of demonising their opponents, a former ambassador says.
During a political rally in Pennsylvania, a barrage of shots was fired, with one bullet grazing the ear of second-time presidential hopeful Donald Trump.
The attack has rocked America, but Australia's former ambassador to the US Arthur Sinodinos says it wasn't unexpected.
"I'm surprised it's taken this long for something like this to happen," he told AAP on Monday.
"Given the amount of polarisation in the US, the amount of mudslinging that goes on, the attempts by each side to demonise the other, it's not surprising.
"There's been such a normalisation of very unusual behaviour in recent times."
In Australia, compulsory voting, preferential voting and an independent electoral commission bolstered stability but Mr Sinodinos says local politicians still have a role to play.
"It also comes down to leadership character: people not just saying the right things, but doing the right thing," he said.
"Hopefully ... Australian politicians on all sides will take the lesson out of this.
"If (they) seek to demonise and dehumanise your opponents - whatever side of politics they're on - crazy people come along who might take that as some sort of indication that they should do something about it."
Australia's current ambassador to the US Kevin Rudd and former prime minister Malcolm Turnbull both denounced the attempt on Mr Trump's life on the social media platform X.
Mr Sinodinos' predecessor Joe Hockey said while there was a "deep level of shock" that would undoubtedly affect the November presidential election, the attack wouldn't deter President Joe Biden from running again.
"Joe Biden, if he decides not to run now, he would look like a coward, he would look like he fears the assassin's bullet," he told Sydney radio 2GB on Monday.
Australian political leaders have condemned the assassination attempt, with Prime Minister Anthony Albanese noting heightened concern following the shooting.
"It was a shock to the system, we know that increasingly United States politics has become very polarised, and tragically, there is a history, of course, with violence," he told ABC Radio on Monday.
"It's a great thing that in Australia by and large, politicians - including the prime minister - can wander about events and can walk around safely.
"(The respect for democratic processes) is a good thing we have here, and it's important that we don't take it for granted, it's important that democracy be cherished."
Mr Biden has ordered the country's Secret Service to review security measures ahead of the Republican convention.
Treasurer Jim Chalmers said there was relief Mr Trump was OK.
"We've seen politics get uglier and more polarised and unfortunately, more violent, and I think a lot of people around the world and around Australia are worried about those developments," he told Nine's Today program on Monday.
"We can't see this extreme polarisation, this extreme violence, be normalised in democracies around the world, we're supposed to settle our differences with votes, not with violence."
Shadow treasurer Angus Taylor said while America had become politically divided, violence was not the solution.
"The whole point of democracy is we get our chance to have our say at the ballot box and that's true in any great democratic nation," he said.
"We've got to keep coming back to that and calling out completely unacceptable behaviour, clearly, and it's not what we want to ever see here in Australia."
Opposition home affairs spokesman James Paterson said Australia cannot be complacent about threats to elected officials or candidates.
"While it's true we've got very different gun safety regulations ... there are some troubling signs that there are trends towards using violent means, in Australia, to try and intimidate parliamentarians and their staff," he told ABC radio.
"We cannot allow that to take hold here."
