It's just that in my own experience in the liquor business, where some salesmen carried and most didn't, the people who carry guns are more likely to get messed up, and I never knew anyone who was saved by their gun, I did know people who acted stupid with their guns and got the crap beat out of them. I've had guns pointed at me three times, the last guy was shot by the police, his gun wasn't even loaded.

Accidental gun deaths invariably involve gun owners or their family.
Suicide attempts are much more likely to succeed when a firearm is available.
Most murders are heat of the moment arguments, turned lethal by the presence of firearms. People actually defending themselves from crime with firearms is an extremely rare situation.
80 people a day are shot to death in the US, here's a breakdown.
The New York Times > Week in Review > Image > An Accounting of Daily Gun Deaths

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“ The subjects of every state ought to contribute towards the support of the government, as nearly as possible, in proportion to their respective abilities; that is, in proportion to the revenue which they respectively enjoy under the protection of the state.”

Adam Smith , The Wealth of Nations 1776

"We have always known that heedless self-interest was bad morals; we know now that it is bad economics"
FDR's second Inaugural Address