States would become mini warlord kingdoms over the years.
Sorry, but that doesn't hold water. Not to say that there's no way that such a thing
could happen, but it doesn't logically follow from the premise. The powers explicitly granted to the federal government in OTL are of course quite limited, but you'll note that the USA didn't splinter into warring kingdoms in the 1789-1859 period... and the Civil War that came thereafter certainly had more fundamental causes. (If anything, a total "states' rights"-oriented Union would completely avoid the Civil War... because federally abolishing slvery would never even be a distant option. Which is horrible for the obvious reasons, but still proves that "decental union =warlord kingdoms" is a pretty far-fetched conclusion.)
Now, I won't lie: personally, I'm a fan of organisational diversity (and thus of decentralism,
provided human rights are centrally guaranteed). This may colour my views to some extent. That said, regardless of personal preferences, AH is just about what's
interesting. I'll enjoy a good Federalist-wank as much as the next guy. I just brought the issue of states' rights up here because the suggestion for this kind of law was brought up by Hamilton of all people, and because if worded in a certain way, it could end up being exactly the
opposite of what he wanted. From an AH perspective, that's interesting. And kind of funny.
But what would the outcome be, in actual fact? Some kind of super-weak union destined to fail? I think not. It would merely mean... the kind of constitutionalist approach we saw in 1789-1859 in OTL. That is: a rather small federal government that is limited to a few key tasks (and most of them relating to foreign affairs), while the states typically enjoy primacy domestically. Only as of the Civil War did this begin to change, in part because the side that had tied is cause to the idea of "states' rights" ended up losing. But also because the settlement of the whole slavery issue was ultimately forced by the federal government, thus beginning the shift of domestic political primacy from the states to DC. Finally, there was the interesting question of secession itself. Technically, if one reads the tenth amendment literally, secession
must be a prerogative of the states. The Constitution doesn't mention it, and anything not delegated to DC by the Constitution is reserved to the states. This was (from a legal perspective,
very sloppily) brushed aside in
Texas v. White-- in 1869, with the Civil War fresh in memory. I wouldn't call that an apolitical verdict, but it is what it is. It started a long tradition of studiously ignoring the tenth amendment.
From this political situation, the current state of affairs arose. The federal government gradually took on ever more tasks, and often tasks that are not and were never delegated to it by the Constitution. Whatever one may think of it, it's the way it is. But it's not the way it's always been, or absolutely had to become. If the federal government hadn't taken on the many, many new tasks it has since the latter 19th century, we may assume the states would have done it. As I always say: look at Europe. The EU has no union-wide departments of education, health, etc. ...the member-states each do it. Since its conception, the EU has nevertheless seen fit to function without descending into warlord statelets. If the kind of legal rule discussed in this thread had been introduced (and worded in the way I suggested) in the USA... well, the USA would just be more like the EU, as far as division of tasks and powers between states and DC would be concerned. This, too, is interesting from an AH perspective.
Needless to say, there would be other potential outcomes.
@CaliGuy asked (and I completely missed that earlier, sorry!) how the USA reconciles its many federal powers with the tenth amendment in OTL. What I wrote about
Texas v. White gives it away: many things are just not really reconciled at all. The tenth amendment has largely become a dead letter. From the way I treat the subject, I'm sure it's clear that this irritates me. Not because I fundamentally object to any kind of central power, but because I think just ignoring an amendment you don't like is sloppy. So, supposing the kind of legal provision suggested in this thread had been introduced, and supposing that its exact wording forced courts to scrap all laws that conflict with any part of the constitution... would that just freeze-frame the whole US government in its limited antebellum form? Maybe. But maybe, the Constitution would just have seen more amendments, designed to grant new (clearly defined) powers to the federal government. Legally, at least, it would have made for a much more correct solution.
In any event, my point remains that depending on the wording, the kind of legal provision under discussion in this thread either does very little,
or fundamentally stops the OTL growth of federal power (while not prohibiting an ATL way for federal power to still expand). But even if it's the latter... a collapse of the Union seems a very unlikely outcome.