They should be saying that already, with the UK and Australia as examples among others.
There's a reason why this sad nutter went to NZ.
https://www.bbc.com/news/world-australia-35048251BBC:
"We have an opportunity in this country not to go down the American path."
Those were the words of former Australian Prime Minister John Howard before he radically changed Australia's gun laws and - many believe - rid the country of gun violence on a large scale.