> When you study the US Constitution (kind of assuming that's the one you're referring to) do you also study its amendments as thoroughly?

Absolutely. Having skipped over the second amendment for a long time because I thought it was boring, I have a fairly recent bit of study to recall from. For context, I always believed (basically) as the ACLU does that the second amendment was a collective right, and that regulations were good, necessary, and all that jazz. It wasn't until studying the previous drafts of it, alongside Madison's other lost amendments, going through the Federalist Papers, Madison & Hamilton's archived documents, et al, that I arrived at the contrary conclusion -- the second amendment is an individual right that even the existing regulations for it are probably counter-Constitutional.

> Do you think that this fits in with the role of the constitution necessarily?

Not per the original Constitution, but as of the Sixteenth amendment, it decidedly is. That said, I don't believe that it was intended for our nation by its founders, but that's why the Constitution is indeed a living, breathing document, and amendment is the cure for whatever ails it. Looping back around to the second amendment, if "the people" believe that the second amendment is more harmful than beneficial, then the remedy isn't to violate the Constitution by infringing the right through laws, but to amend the Constitution to modify or repeal the second amendment. It takes a lot to get there in terms of popular support, but if there's a high bar to eliminating rights of others, that's a feature, not a bug.

> Does it even have to for it to be obvious that it's a good idea that the founders didn't codify into the constitution because it was so foreign a concept to them at the time?

So, there are many policies that I think are "good ideas" that are unconstitutional. I can make an acrobatic argument in support of public defender, but in simply dealing with negatively asserted liberties (as the Constitution enumerates) vs. positively asserted liberties (which a public defender is, and which the Constitution doesn't espouse), it's not terribly well founded. Personally speaking, I am glad that public defenders exist, and I am glad that there's a state-funded barrier to due process punishments imposed by the state, and I think that it is overall a net good... but I don't think it's terribly Constitutional, barring amendment.

That was kind of a non-sequitur, but to answer the question of whether or not I think it's appropriate for the federal government to intervene, that answer is predicated largely more on 'HOW' they might intervene than whether it's a good idea or not. It very probably is a good idea, and there are likely ways in which the federal government is empowered by the sixteenth amendment that are constitutionally sound, but there are many other ways in which we bolster our least performant states that are not necessarily Constitutional, even barring the sixteenth, which does not completely override the limitations imposed by Article I, Section 8 without a dramatically liberal reading of "General Welfare".

In short, it's very complicated, and you can usually pick out the other students of law in public forum by the nuance of their arguments. I think that publicly funded health care is a good idea, but I don't like the way it's implemented, and object vehemently to the individual mandate, irrespective of everything else. Similarly, I understand the conservative objections to the civil rights act, which clearly did objective good, but also included a rather subtle power grab that has largely contributed to our abundant prison populations to which I object. Life is complicated. The Constitution is complicated. And even where we can divine objective truths from it, there still exists a myriad possibilities of subjective application, which could all be truthy.