US is in a nice club of countries when it gets to intentional homicide rate:
Point is, they shouldn't be there. They are so much richer, stable and developed than the rest of the countries there, that it doesn't make any sense at all.
Reason is of course easy access to guns, of which around 75% of their homicides can be attributed to. (2012: 8,897 firearm related murders)
Now, how fucking thick you have to be, to understand that having lots and lots of guns makes it more likely to use one? It's a quick, effective and safe tool to ensure murder for the killer. It's much less messy than using a knife, especially now that DNA goes everywhere. It's also way easier for suicide than to hang yourself or other slow, painful or unsure methods that require planning and meticulous execution. (Buy, get medicine, be guaranteed alone for hours or whatnot. Many people change their minds or are unable to successfully do it when they are in that mood. A gun is a press of a button. )
I can kind of understand it if you are a criminal, or under high risk of violent criminal activity for some reason. Or if you simply love guns. (Guns are fun, I shot the G3 and mp5 in the army, was even a decent shooter.)
I understand the country is flooded with guns, and it would be a long undertaking to reduce the amount, but you have to start somewhere. And that is, to at the least, ensure that if people want guns, they have to be a member of a club, take a shooting exam, and know how to use and store their firearms. Maybe even a mental checkup/doctors paper every 4-5 years. It really isn't too much to ask, similar things are required for drivers.
The 2nd amendment was made in a completely different time, refers to a regulated militia, where guns were large and slow firing muskets, not something you stuff in your pants.