My extremely annoyed viewpoint after having a discussion with my older brother who is consistently unable to form logical arguments.
The 'mental health' argument is ridiculously vague and a cheap cop-out to justify how one gun owner is different than another. My older brother has an assault rifle and 2 handguns. Myself and my younger brother are both against the perversion of the 2nd amendment (extremely opinionated statement of course). My younger brother also has bipolar. He displayed no signs of bipolar until he was 20 and then had an episode that triggered it. My older brother had these guns prior to my younger brother's diagnosis. What happened if he took those guns the day his illness was triggered? In addition, we're lucky enough to have good healthcare to pay for treatment and have it diagnosed in the first place. Sure there are red flags that pop up in some cases, but that's not always true. As has been mentioned, even if my younger brother was denied a gun, he still has access to one. I also have epilepsy, and have had it my entire life. It took a long time to properly diagnose. I have a friend who has the EXACT same epilepsy as me, but had her first seizure at 24. The brain is a weird organ, and it's impossible to truly and accurately predict. Focusing on the prevention of different outlets is significantly easier than focusing on how to prevent them from thinking of that outlet.
People WANT guns, they don't NEED them. Often, they believe the 2nd amendment gives them the right to defend themselves. For every 1 case of defending themselves there are 4 cases of unintentional injury. Due to the numbers, they are actually endangering themselves. They ignorantly (or intentionally for that matter) endanger themselves and then use self-defense to justify the need for the 2nd amendment. From 2nd amendment justifying the right to defend, to the right to defend justifying the 2nd amendment. Talk about a logical argument

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Regardless of all of the "2ND AMENDMENT" vs. "NUH-UH" arguments, people vote their wallet regardless of the rest of the crap that goes along with it. Here is my proposal:
Medical costs of gun injuries over our lifetime will cost tax payers $1.1b. Using both the population and average years spent working, this amounts to $78,000 in taxes per person over their working career, or $1,733 per year. Let’s switch that into household numbers. The average household will spend $212,560 over a lifetime, and $4,724 per year. ~40% of households own guns. Let’s say you only tax those who choose to own a gun: $531,400 lifetime, $11,800 per year. ~18% of households own handguns (which is generally the issue of targeting people vs. animals). $1,180,890 lifetime, $26,242 yearly. Feel free to own a gun, just understand the costs associated with it.
Not necessarily practical, but a reasonable thought experiment. Although, it might increase bank robberies to pay for the taxes...
By the way, the kindergarten teacher has an assault rifle so she can go to the shooting range and shoot paper targets of people. <-- another statement coming from recent annoyance.