Andrew Leigh is a member of the Australian Parliament and a former professor of economics at the Australian National University.

Australia experienced its deadliest mass shooting in 1996 after Martin Bryant killed 35 people in and around the Port Arthur tourist site. Twelve days later — before all the victims had been laid to rest — Australia's police ministers met and unanimously agreed on measures to tighten licensing and registration requirements, restrict access to semiautomatic weapons and limit sales.

The national government coordinated a buyback program, which paid market prices for guns that were handed back. Over the next year, more than 600,000 firearms — about one in five of all guns in Australia — were handed into police stations. Given the harrowing loss of life in the United States to gun violence, it's worth understanding the impact of these reforms.

Did the Australian buyback stop gun massacres? Following the tragic mass shooting in Las Vegas this week, some have dismissed Australia's buyback as ineffective, asserting that mass shootings were too rare in Australia prior to the buyback to show any clear evidence of progress.

Alas, that isn't correct. Australia experienced an average of one mass shooting — defined as the killing of five or more victims in one incident — per year in the decade prior to 1996. In the decade after, no mass shootings took place. The chance of this being due to luck alone is less than 1 in 100.

But most gun victims don't die in mass shootings. The person most likely to kill you with a gun is yourself, followed by your spouse and other household members. After the Australian reforms, I set out with Wilfrid Laurier University economist Christine Neill to analyze how the reforms impacted gun homicides and suicides.

We first looked at national trends and found that the rate of gun deaths had been falling for the decades prior to 1996. Time series econometrics suggested that the reforms had caused the death rate to fall a little faster.

In a second study, we then looked across states, to see whether those places where more firearms were bought back also experienced a larger drop in gun deaths. We found a clear pattern: The greatest drop in guns per person occurred in Tasmania, which also saw the biggest fall in firearms suicide. The smallest reduction in the firearms ownership rate was in Canberra, which also saw the smallest drop in the firearms suicide rate. We did not find evidence of an increase in other forms of homicide (such as stabbings) or suicide (such as deliberate overdoses).

Overall, we estimated that the Australian firearms reforms of 1996 save around 200 lives per year. Most of the averted deaths are suicides. Given that the buyback had a one-off cost of around half a billion Australian dollars, this makes it one of the most cost-effective public health measures in Australia's history.

At the time that we published our research, I was an economics professor at the Australian National University. Today, I sit in the Australian House as a member of the opposition Labor Party. It isn't in my partisan interest to praise the results of the 1996 reforms; although my party supported them, they would not have happened without the leadership of conservative Prime Minister John Howard and his deputy Tim Fischer. Their reforms saved lives, but they paid an electoral price during the 1998 election, when mainstream conservatives lost ground to far-right populists.

Still, it's hard for me to look at the United States today and wonder what might be possible if the Republican Party had some leaders with political courage similar to that of Howard and Fischer.

Australia still has an active shooting culture. My morning run sometimes takes me past both the rifle range and the handgun club. When there are too many kangaroos in the bush behind my house, the government calls in the shooters to cull the numbers.

But what we don't have is a culture in which loaded guns are kept in bedside tables, stowed in gloveboxes and tucked into the waistbands of young men out on a Saturday night. On a per-person basis, the United States has a gun ownership rate that is seven times higher than Australia's and a gun death rate that is 11 times higher.

How did Australia manage to act quickly and save thousands of lives? Leadership.