While there may be more people available to stop gunmen because of the access to guns, increased access to firearms increases the number of firearm related accidents. This is really something that comes with the territory. No matter how much gun safety is taught, there's always going to be a distribution of people who fall outside of safe usage of guns. At that point, you have to consider whether, as a nation, does the number of casualties based on this incident outweigh the potential number of casualties based on firearm related incidents caused by increased proliferation of guns?
> According to the Centers for Disease Control and Prevention, in 2013, firearms (excluding BB and pellet guns) were used in 84,258 nonfatal injuries (26.65 per 100,000 U.S. citizens) [2] and 11,208 deaths by homicide (3.5 per 100,000),[3] 21,175 by suicide with a firearm,[4] 505 deaths due to accidental discharge of a firearm,[4] and 281 deaths due to firearms-use with "undetermined intent"[5] for a total of 33,169 deaths related to firearms (excluding firearm deaths due to legal intervention).
So, 11,713 homicides and accidents in the US, not counting suicide. This week alone, gun will likely kill more Americans than the attack on Paris today.
Because the three most common causes of accidental death in the US are Unintentional fall deaths, Motor vehicle traffic deaths, and Unintentional poisoning deaths. And each of those kills roughly three times as many Americans as guns.
When you add in intentional firearm deaths, it's roughly the same as automobile deaths -- yet we give 16 year olds the keys without a second thought.
Snark aside, I think we're talking about different problems. The comment I'm replying to proposed that arming citizens will solve (or mitigate) the problem of terrorism. I pointed out that the proposed solution will kill orders of magnitude more people than terrorism itself. Automobiles are a separate problem.
A guy with a gun isn't going to be as brave when he knows others probably have guns too. And most shootings are intentional.
So it seems no more dangerous to arm everybody. And possibly far less dangerous. Not to mention that many other types of crime would likely decrease as well.
You know, because of the threat of getting shoy by your would-be victim.
eg.,:
http://www.theguardian.com/news/datablog/2012/jul/22/gun-hom...
Brazil, Italy etc. - significantly lower percentage of firearms between citizens (say compared to USA), yet there are percentually more homicides performed with firearm.
Brasil on the other hand has indeed much more homicides per 100k people than the US, although having only an 8% of the population legally possessing a weapon.
TL;DR: In Italy there are four times less homicides by firearm per 100k people than in the US.