1. "Guns don't kill people. People kill people."
This is a fantastic argument for those who can't tell the difference between one death and a dozen. Absolutely, a murderer can often kill one person or two with a knife before being stopped. But to really rack up those mind-blowing death counts to make sure that many lives are destroyed and families ruined in the space of five or 10 minutes you need a gun. If all you care about is apportioning blame and declaring that someone does or does not have murderous intent, then by all means, claim a knife and a gun are equivalent weapons. For those of us who are more worried about preventing unnecessary deaths than merely acknowledging the hate that resides in some people's hearts, however, the sheer amount of damage a gun can do is reason to limit who can get their hands on one.
2. "The only thing that stops a bad guy with a gun is a good guy with a gun."
If you prefer pithy sayings to hard evidence, I can see why this would be convincing. But if you look at the real world, you'll find that far from being our only hope, good guys with guns are barely any help at all. No mass shootings in the past 30 years have been stopped by an armed civilian; in 1982, an armed civilian successfully killed a shooter, but it was only after he committed his crime.
It's not that there aren't enough guns, either. There are as many guns as people in this country, and fully a third of people are armed. Even when shootings happen in gun-happy places, where armed people are sure to be nearby, this vigilante scenario simply doesn't work. That's because pulling a gun out and shooting back in the chaos of a mass shooting just makes things worse, as was discovered when a would-be hero at the 2011 shooting of Gabby Giffords very nearly shot the wrong man. (The actual shooter was tackled by an elderly man.)
3. "But, mental health!"
Opponents of gun control love bringing up the problem of inadequate mental health care after a shooting. This is strictly for deflection purposes, as there is no indication that Republicans will ever work on meaningful reform for our mental health systems which, it's true are woefully inadequate. It's an issue that only matters to them in the immediate aftermath of a shooting then it's forgotten, until there's another shooting. Rinse, repeat.
Also, the "mental health" gambit, in this context, is always vague. What exactly is the plan? Round up everyone with a mental health issue and put them under lock and key? That amounts to 1 in 5 Americans, the vast majority of whom have no violent tendencies. Will we have some kind of extensive mental health registry? A lot of Americans who struggle with mental health are undiagnosed, though, and putting them on a government list that restricts their rights is not a great inducement to get a diagnosis. There are a lot of shooters in this country, so we have some pretty good data on mass shooters. And that data shows there's no reliable way to tell who is going to go off like this, and only 23 percent of shooters have a diagnosis. Even if all of those individuals got gold-star treatment, the system would only stop a few shooters.
4. "Second Amendment, baby."
Here's a good time to remind everyone that the Second Amendment was written by slaveholders before we had electricity, much less the kind of weaponry that would-be murderers can buy today. But sure, if you think it's that precious, we can compromise: If you love the Second Amendment that much, feel free to live in a powdered wig and shit in a chamberpot while trying to survive off what you can kill with an 18th century musket. In exchange, let those of us living in this century pass some laws so we can feel safe going to class, or the movies, or anywhere without worrying that some maladjusted man will try to get his revenge by raining death on random strangers.
