When the United States was founded, the word "state" had a very different meaning. Unlike today, where a state is closer to a subsection of a country than a country in and of itself, back then, an independent entity is exactly what it was. So the United States of America was actually more like what the Euro Zone is today than its own modern incarnation.
At the time, there was a massive debate between Alexander Hamilton and Thomas Jefferson about the topic of localization versus centralization of government. Hamilton favored centralization, while Jefferson, who was from Virginia, feared northerners controlling him since the lifestyles were so very different, and as such favored localization. The compromise that they came to was nothing short of genius, in my opinion. That said, it was designed for a specific world as a result of specific circumstances, and our world is very clearly orders of magnitude different from the world for which it was designed.
Let's take a step back for a second and talk about the advantages of each. Since the role of government; as a monopoly on force; is to maximize market efficiency, centralization makes sense in many ways. There are economies of scale associated with more centralized governments, so market inefficiencies that are universal across the country will be better served in general to be regulated at the federal level. It is efficient to have a universal currency, a drivers license that works in every state, large social safety net initiatives being managed at a federal level, etc. That said, there are issues with centralization, which is where localization has its role. Large governing bodies can take a while to get things done. There is bureaucracy to deal with, a lack of focus, and at times an inability to understand how local culture effects a particular situation.
These pros and cons will always be around, but as the world changes, so too does the weight of each. In 1776 when the Declaration of Independence was signed, getting from Boston to Richmond was not an eight hour drive or a one hour plane ride. We couldn't call someone on a cell phone and have a real time conversation, or video chat in real time over Skype. Clearly in such a world, localization is of the utmost importance in most aspects of life. The primary reason for the uniting of the states was the economies of scale associated with a federal army, but in few other things would it be advantageous. However, since this question is so dependent on transportation and communication, as these improve, government needs to change, with the trend moving toward more centralization to continue to take advantage of economies of scale.
Just 100 years after the signing of the Declaration, the world was much different. Telegraph communication could get a message across the country at the speed of electricity, the invention of the steam engine allowed for trains and ships that could carry massive loads across great distances quickly. With the effective size of the world dramatically diminished, is it any wonder that we would want to correct for this change with the biggest expansion of federal powers ever, the 14th amendment?
This question of federal versus states rights comes up all the time in modern day politics, and certainly much more than it should. The intent of the debate was the one discussed earlier, but a strict reading of the text as opposed to the intent of the text results in trying to frame modern issues with an 18th century mindset, which is akin to ignoring 200 years of technological development;. to ignore that I can access just about any information I could ever ask for from a 5oz device in my pocket; to ignore that I can buy a plane ticket in New York from a laptop in my bed at noon and be partying in Miami by six. Imagine a world in which we have an elaborate transportation system built on teleportation technology, where one could get from New York to Dubai in less than half a second. In that world, how does the question of localization versus centralization of government change? How does the definition of a "country" change?
Politicians (or at least their campaign managers) are not stupid. Disingenuous, yes. Stupid, no. When a political figure attempts to make an argument for a particular law or right to be relegated to the state, the vast majority of the time this is his way of finding a loophole in the law, rather than standing up for what he actually believes in and outright saying that this right should be allowed. Politicians are too afraid of the "do-gooders" who take altruism and self sacrifice as their standard of value to ever say this outright. Of course, if the question is actually about states rights, then the debate is very different. It's numbers, it's intellectual. How effective is regulating X at the state level versus at the federal level, based on the evidence? How cost-efficient is regulating X at the state level versus at the federal level, based on the evidence? Agreement on the facts results in agreement on the policy.
And that's the point. That is why we desperately need a rational basis amendment in this country. Our country was founded on a morality of indivualism; on a morality based on the inalienable rights of "life, liberty and the pursuit of happiness" (might remind you of something). That's why this blog exists. So the adults can talk. This blog exists to reframe the debate in terms of reason. Disagree with me if you choose, but disagree with me on the facts in the context of an intellectual debate. The constitution is a living document, the legal code is a living document. It is outlets like this where we can discuss what the laws should be, not what they are or how difficult it would be to modify them.