We may not share borders directly with other countries, but there are these things called boats which like to pop over to our thousands of kilometres of unprotected coast line and drop stuff and people off (that was and is still a rather large political football).
As for the illegal drug trade, it is alive and well unfortunately.
Granted the we don't have the same ideas about guns and gun ownership here (that is a much larger social change for the US) so how things are implemented in the USA will be different.
Easy access to a gun is a bad thing.
* I hear way too many stories about children getting guns and shooting themselves or someone close by. These news stories are non existent here, that sort of thing does not happen.
* We can generally associate mass shootings with People who are having a really bad day who also have easy access to a firearm.
What happened here was:
* a gun buyback and amnesty. That removed a lot of the easy access to weapons. That also had the effect of making them a scarce resource (and capatilisim being what it is, made anything already out there more expensive, even for the criminals)
* You need a gun license and a reason to own a gun (i.e. you are a farmer or are part of a gun club)
* You need a special license (and reason) for anything that is semi automatic, no fully automatic weapons are allowed
I challenge you to find a solution that *would* work for america. Take a look at other 1st world countries and find out where they went wrong and where they went right. Do some reason for the opposition arguments.