The UN is using the Mexican Gun Lie to try to trash the 2nd,

right along with the gun bigots here in the US:
Last week President Barack Obama announced cooperative measures with Mexico, building on earlier initiatives launched by President Felipe Calderón. A few days later, Secretary of State Hillary Clinton acknowledged shared responsibility, stating that America’s demand for drugs funds the cartels, while the flow of U.S. guns into Mexico gives cartels huge fire power. As she said, even “if you’re the strongest pro-gun person in America, you have to stop and ask your self ... why should we be the source of their problem?”
Except we already know that this is a lie; the military arms the cartels are using, the select-fire weapons and machine guns and RPGs- are being smuggled into Mexico along their coasts and southern borders; NOT from the US. But they keep telling the lie, because it fits what they want to do: trash the 2nd Amendment.

I know that the last thing many Americans want to hear is a senior U.N. official telling law-abiding citizens to curtail their Second Amendment right to bear arms. I’m not doing that. At the U.N. we fully understand the fundamental importance of constitutional rights and respect for the rule of law.
And when they lube you up like that, you know what's coming next:
But there’s a big difference between upholding the right to bear arms and illegally smuggling weapons across the border. Gun-running presents a clear and present danger to law-abiding citizens in Mexico and the United States, and to vulnerable communities in Central America that are caught in the cross-fire of violence.
Nice; the UN bigshot equates us defending our right to arms with smuggling and murder. And not one damn word about where and how the arms are actually getting into Mexico. And here comes the part where he shows his true regard for our Constitution and the rights we hold dear:
It is therefore heartening to hear recent statements by senior U.S. officials in favor of more vigorous enforcement of national laws that prohibit sales of unlicensed firearms to foreigners. We especially encourage the debate on the issue of reinstating the 1994 U.S. ban on assault rifles that expired in 2004. And we support further debate within the United States on whether to close the gun show and private sale loopholes in existing U.S. laws, which create boundless opportunities for criminals to acquire illicit weapons. These legislative changes do not affect law-abiding hunters and sport shooters in any way.
I'll add to what Sebastian already said: Screw you. The 2nd Amendment doesn't say one damn thing about 'hunting and sport shooting'; it speaks of the right to arms that belongs to all free people. And, in particular, that right being the 'doomsday provision' in the face of a government become tyrannical. And you want to trash that right, a little at a time, and you'll lie to do it, because you don't like the peasants having arms(it can make them all uppity and hard to order around).
But the problem requires a broader solution — one that is consistent with the new U.S. commitment to cross-border cooperation. There is a tough piece of international law that can help. In 2000, U.N. member states adopted a Convention against Transnational Organized Crime, to fight jointly international mafias of all types — including the Mexican drug cartels. Congress ratified this convention in November 2005, but not the specific protocol against the manufacturing and trafficking of firearms(which, as I recall, basically says "You are not allowed to own one). Indeed, although the U.S. was active in negotiating the protocol it has not even signed it yet. Becoming a party to this protocol would help stem the flow of weapons that are wreaking havoc along America’s border.
"You have to do it, for the children and for Mexico!"
And here it is:
How? By recognizing that the gun laws of individual nations alone cannot solve the problem of cross-border crime and therefore must be mindful of international standards.
Translation: "You have to let the UN have control of your law enforcement, and the writing of your laws, so that international standards(you know, those oh-so-progressive ideals to disarm all but government minions) can prevail." Take a look a the next paragraph: they want registration, they want all sales to have to go through official channels, they want control of our law enforcement so things will work well 'across borders'.

Go to hell, Mr. Costa. We have no desire to, and will not allow anyone else to, destroy our Constitution and throw away our rights just to make you and all your statist friends happy.