The horror of a mass shooting has brought about stricter gun control in one country - Australia.
In 1996 when 35 people were killed and 23 wounded in Port Arthur, the Australian government moved swiftly to tighten gun control. It banned automatic and semi-automatic firearms, adopted new licensing rules, set up a national firearms registry, and introduced a 28-day waiting period for people wanting to buy guns.
It also bought and destroyed more than 600,000 civilian-owned firearms. Since then there have been no mass shootings in the country. Tim Fischer was the deputy prime minister of Australia at the time, and the man charged with implementing the gun controls despite widespread opposition.
He says an effigy of himself was hung in one rural town, but the measures had an effect. Later Mr Fischer "tackled Americans" when working as an ambassador in Rome.
"I now make them squirm, I say 'you have a duty to stand up to the NRA'."
Mr Fischer also recommends issuing trade sanctions and travel warnings for people visiting the US.
