I do have to plead a certain amount of ignorance here. I thought the Brady Law was simply a waiting period for all buyers, plus a denial of the automatic right to own a gun to certain felons. Neither, in my opinion, would violate the Second Amendment. (The language of the Second Amendment says "of the people," which suggests a certain concept of the good citizen. That some small class of dangerous people can be kept from owning weapons. There is no such terminology ("of the people") in, say, the First Amendment. A law forbidding an ex-felon to speak freely on public issues would be blatantly unconstitutional.)
If the Brady Law goes beyond what I've described, then I'd agree that it does, or might, violate the Second Amendment.
But I would still point out that it was enacted a decade ago by a Democratic Congress. I know it was renewed, but that's different. To me, if you want to show that we aren't making progress on gun rights, let alone show that we're losing on gun rights, you'd have to show that new laws or regulations that are now occurring, or about to occur, serious enough to outweigh the progress we've clearly been making, currently and much more recently than Brady, on concealed-carry.
Wrong
First Amendment: ...or the right of the people peaceably to assemble..."
How long a waiting period would the Second Amendment allow? A week? A month? A decade? Do please bear in mind that one of the design goals of waiting periods is to increase the hassle of purchasing a firearm. Someone who does not live conveniently close to the point of purchase must make two trips. If the gun store is 45 minutes away, that's 90 minutes of the purchaser's life wasted. Any reason that much hassle is okay, but requiring the person to show up ten times, on separate days, to buy a gun wouldn't be?
Also, while states have the authority to brand convicted felons as slaves who are forbidden from owning firearms, and while the Second Amendment and the "full faith and credit clause" would probably allow for some federal statutes that would make such prohibitions issued in one state applicable in others, explain how the federal government has the authority to declare that anyone convicted in any state court of any crime whose sentence could be more than 366 days in prison (regardless of the actual amount of time to be served). Shouldn't the question of firearm prohibiton be a matter for the sentencing state's government to determine?
So does the fourth amendment. You think convicted criminals who have served their full sentences have no right to be free from unreasonable searches and seizures? The courts have rulled that anyone who lives here is part of the group "The People" in conjunction with fourth amendment rights.
From Findlaw:
Another matter of scope recently addressed by the Court is the category of persons protected by the Fourth Amendment--who constitutes ''the people.'' This phrase, the Court determined, ''refers to a class of persons who are part of a national community or who have otherwise developed sufficient connection with [the United States] to be considered part of that community.'' 28 The Fourth Amendment therefore does not apply to the search and seizure by United States agents of property that is owned by a nonresident alien and located in a foreign country. The community of protected people includes U.S. citizens who go abroad, and aliens who have voluntarily entered U.S. territory and developed substantial connections with this country.
(28) United States v. Verdugo-Urquidez, 494 U.S. 259, 265 (1990).