Having grown up in the USA, I can safely guess that we here will never do more than philosophise about the prevalence and deadliness of guns in the USA. One commentary I read noted that if the fellow had used a 6-gun instead of a Glock 9mm, he would have had to stop shooting much sooner, and could not have exacted such carnage.

After the Port Arthur Massacre, we in Australia drastically limited access to semiautomatic weapons. I hope that lawmakers in the US can move somewhere in that direction.

Before the 6-shooter, there was the muzzle loader. That was the kind of gun considered by the men who drafted the second amendment to the US Constitution, in 1791. I wonder what the Founding Fathers would think of the consequences of the second amendment as it has been interpreted to the advantage of US gun manufacturers and their advocates.

to attribute mental instability to shooters who target many people is an insult to the truly mentally disturbed, most of whom are quite peaceful.

this is a convenient rationalisation, it seems to me, by a society obsessed with safety and security at all and any costs, and shows how ideology can imprison a whole society.

by espousing the divine right of the individual to bear arms, this evil ideology ensures neither life, nor liberty, nor the pursuit of happiness.

The USA has a 'culture' of armed citizenry. That's not going to change easily. But hey - look at Australia. In a country with a history of relatively responsible firearm ownership, there was a massive knee-jerk reaction to the Port Arthur killings that effectively turned legal legitimate firearms owners into 'psuedo criminals'. The ownership, licencing and storage over-regulation has been the wet dream of some intellectual public servant think-tank. The costs, including the amnesty buy back of surrendered auto and semi-auto weapons runs into many millions.

Yet I ask: What has been the overall effect of this legislation and the return on investment?

Has the incidence of crime, injury and deaths by firearms decreased in that time? (Please do not include suicide deaths since anyone determined to snuff themselves will find an alternative)

I don't know the statistics but someone will - or where to access.

However it is abundantly clear that criminals have no trouble whatsoever acquiring weapons of all descriptions and that crimes involving firearms are committed on a daily basis. A highly regulated heavily restricted 'culture' has created a profitable black market in illegal weapons while police are required to waste time doing Gestapo like checks on licenced owners.

It is an unfortunate fact that lunatics occasionally embark on murderous rampages. Yes - having guns can make such a person very effective, but we've also seen instances of carnage achieved with knives, vehicles, fire and poison. Sad fact is unless some foolproof method of identifying potential perpetrators of mass murder is found there will be more incidents to come.

It seems the Tucson killer showed disturbing signs of mental instability well before the shootings. Grave pity that those close to him were unable or declined to seek intervention, although this is a widespread problem here as well. Too often 'authorities' only want to take action after a crime is committed.

My sympathy goes out to the families of the deceased and to those wounded - in body and mind.

"to attribute mental instability to shooters who target many people is an insult to the truly mentally disturbed, most of whom are quite peaceful."

Yes SHRODE - most mentally unstable people are quite peaceful and moreover only a danger to themselves.

However there are individuals who are DANGEROUSLY unstable who pose an extreme threat. While very much a minority, such people do exist and when they do 'explode' the results are often catastrophic.

Identifying such people and detaining and treating them effectively to contain the paranoid delusions which trigger the violent behaviour remains an elusive goal.