In 1996, a mentally disturbed man shot 35 people dead at a tourist site in Tasmania.
It was Australia's worst ever gun massacre and prompted a crackdown: a gun 'buy back' followed by strict new gun-control laws.
It was the sort of political action that seems inconceivable in the United States. But it was action that seemed to work.
Australia hasn't had a gun massacre since. As gun crime experts pointed out to me when I did a report on it for Al Jazeera , the chance of being murdered by someone with a gun in Australia is now one thirtieth that of in the US.
The Tasmania massacre though, put to bed any ideas that Australian police shouldn't be armed.
They've carried guns, routinely, since the early 1980s.
Australian police though, use their weapons far less frequently than their American counterparts.
Reliable figures are hard to find, but it's generally accepted about 400 people are shot dead by police in the US each year. Figures from the Australian Institute of Criminology suggest the average number killed annually by Australia's police is about six.
Why? It may have something to do with the policing culture.
Take this last year in Brisbane. A disturbed man, in a busy shopping street, waving around a gun. But, for 90 minutes, the police didn't shoot.
When they finally did, they shot with rubber bullets bringing their target down but keeping him alive.
Lee Matthew Hillier was imprisoned for his behaviour, not killed. There may be all sorts of reasons for the Australians' restraint: it's worth pointing out that the whole incident was filmed.
Even so, things seem to be done differently in Missouri.