The NRA’s primary concern is the second amendment. Many conservatives do interpret them in an absolutist fashion. The NRA, in its original form, did not resemble its current form in any way. It was a firearms safety and training organization. It made a turn in the 1950s and 1960s, becoming more conservative in nature, reflecting the broader emergence of conservatism. Their views on the constitution co-evolved with that of broader conservative ideology, albeit focused on a single issue. This is a bit longer of an explanation than you may want, but it is illuminating as it is the cornerstone to understanding from where many different strains of US Politics emerge.
While the NRA specifically concerns itself with the 2nd Amendment, the broader conservative movement regularly embraces “Strict Constructionism” which is the legal philosophy of constitutional absolutism. The main concern of strict constructionist (The formal legal philosophy of constitutional absolutism, which enjoys high popularity amongst conservatives) is the 10th Amendment to the US Constitution, which very simply states:
“The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.”
This is seen by conservatives as the principal bulwark against what they view as government interference in the lives of the American people. It is routinely brought up as the backstop for any argument against government over-reach, or government action in general. The 10th Amendment is valuable in and of itself, as it forces all US Law to derive from the constitution - sometimes through admittedly tortured means, based upon the conventional, general understanding of the 10th Amendment. The absolutist position. however, often rejects this notion, arguing that powers, laws, and legality must be derived explicitly from the constitution - the basic premise at the extremes of this interpretation is that “If the founders didn’t say you could do it, then you can’t do it.”
The broader reason for why they interpret these things the way they do are manifold. For the NRA, the connection is obvious - it benefits their constituency and their own interests for their to be no restrictions on firearms. For the broader strict constructionist philosophy, it is a means of forestalling activism on the part of a government that they view as overly meddlesome, invariably and eternally corrupt, and that was never meant to expand to such a size. If one places the government into the straitjacket of how government was conceived in 1789, then it would be much smaller, less restrictive, less intrusive, and - perhaps most importantly in their minds - require fewer taxes, obligations, and regulations. This would also result, in their view, in a free market with minimalist regulations that they believe would result in massive and unparalleled economic growth. Thus, there is a high degree of synergy amongst strict constructionism, cultural conservatism, 2nd Amendment groups, and free-market ideology, as they are largely co-evolved philosophies. Their current forms began forming in the early 50s, emerged as cogent ideologies in the 60s, but various strains and components of each element of conservatism can be found in deeper American history, with not always favorable results.
But you are correct - their absolutism can be, at times, highly selective. Conservatives were the primary drivers of legislation such as the Patriot Act, which many argued ran roughshod over the 4th Amendment protections against unlawful search and seizure. Some fringe conservatives, during the years that the Democrats controlled the senate and conservatives controlled state legislators, argued against the 17th Amendment (Which established popular election of Senators as opposed to election by state legislatures). There is an entire cottage industry of people, generally conservative in outlook, called “Tax Protesters” who argue vociferously (Also infuriatingly, spuriously, and vexatiously) against the 16th Amendment, which deals with the Income Tax.
Many adherents argue that because the founders were wise, and intended to safeguard us from tyranny, the constitution must be strictly interpreted - there is after all, an amendment process, so if something is truly important, you can simply (!) amend the constitution. Unfortunately, the grand gem of the failures of strict constructionist’s claims to representing the will of the Founders can be demonstrated in the 9th Amendment, which was put in place in direct anticipation of future events (Because the Founders were exceptionally sparky people), namely the evolution of Strict Constructionism, as it again rather simply states, in contrast to the 10th amendment:
“The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others retained by the people.”
The courts, overall, haven’t been terribly enthusiastic enforcing the 9th Amendment. But it does exist. The dynamic between the 9th and 10th amendment is a reflection of the disagreements between the founders which history telegraphed forward into our modern age, and is one of the fundamental dynamic tensions in the US system which arguably makes it superior to other systems, so long as it isn’t treated from extremist viewpoints. The founders were people of strong will, but compared to their descendants, were moderate, polite, and of a profoundly learned, gentlemanly disposition. The constitution was anticipated to function best for a society composed of such individuals.
Indeed. However, unfortunately, history is traditionally profoundly inconvenient for proponents of political ideologies.
The NRA’s general position is to argue two main points:
That having armed citizens, in this instance teachers, leads to a greater likelihood of the attack or shooting be averted, contained, or stopped altogether. This is partly based of an ill-founded notion of how such situations unfold, the associated risks, and how people actually react and respond in such situations.
That any person willing to commit such an atrocity wouldn’t be forestalled by the lack of access to a gun - they’d use a knife or build a bomb or some other such implement of murder. This perhaps ignores the historical fact that guns were invented and developed as a more efficient means of killing people. But, in their argument, controlling guns won’t prevent these tragedies, and that instead, we should focus on the types of individuals likely to commit such attacks, leading us to 3)
That we should pro-actively focus on the mental health needs of disturbed individuals, and promote awareness and reporting of such incidents.