I really don't think that would do it. Criminals and crazies, the ones you need to remove the guns from, are not going to do it. Law abiding and sane people might. Criminals and crazies are both criminal and crazy. If all we had in America was law abiding and sane people then your plan would potentially work.
The Mexico boarder is a joke. Its the entire reason for the whole build a wall thing with Trump. Its especially not going to be more secure if Trump loses in 2020. Well maybe, democrats kind of have a history of being far more brutal than they make themselves out to be. Obama was a huge war hawk and was brutal to immigrants.
Does not matter if they kill a zillion infants every second. Criminals and crazies will never give up their guns. You have to do it by force.
At least I am not the kind of person who conflates right wing politics as being pro gun violence. It actually blows my mind that there are people who have become so partisan that they just think the other side is basically evil.
I want a solution, I want less gun violence. But there isn't a solution right now. One way to reduce gun violence would be to reduce the rise of communism in the country. The destruction of a generation tends to lead to the decline and blowoff phase of a civilization. You end up getting harder times.
I think we are just fucked.