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."Tenthers" have made quite a name for themselves lately, in a resurgence of anti-Federalism, which is all the rage since "that man from Kenya took the presidency." No, that's not entirely accurate; anti-Federalists and those fearing the increasing size of the federal government have been around since the United States' inception, of course. But, since I haven't given much thought to this particular argument until fairly recently, I'm going to offer some initial perceptions.
My understanding of what "states' rights" even means in terms of its practical application is a bit murky. In my observation, the people who so fervently argue in favor of states' rights tend to do so to find a constitutional loophole to maintain their religious and/or patriarchal dominance over their states' population, or to continue oppressing or discriminating against other people for their own gain, without the interference of that pesky federal government whose attempts at curtailing environmental havoc and economic disaster are ruining the richest few's money-hoarding. This, of course, is a prime reason why progressive-minded folks and those on the left express frustration with Tenther's arguments and accuse them of simply being racist, classist, oppressive, and scores of other non-egalitarian things.
On the other hand, consider the effect a smaller federal government could have when practicing democracy and freedom. In a country like the United States, the battles over... well, everything... are next to impossible to resolve. If I were simply a citizen or resident of Minnesota, rather than "The United States," my participation in the democratic process would be far simpler, and far more meaningful. The state is smaller, obviously, making participation not only more meaningful, but easier. My understanding of the inner-workings of other countries is also a bit murky right now, but I think of the European Union. Several different countries, unified in some ways, but maintaining independence of their own. Not being a European citizen, I really can't speculate on how well this works for the people (perhaps some of our European readers can offer their perspectives?), but I do often wonder why the Americas can't do something similar. I have to imagine that many of our more bigoted citizens would balk at the idea of sharing a union of sorts with people from Mexico (job-stealers!) or South America (brown socialists!) or even Canada (white socialists!); but... oh, what the hell am I talking about? I do not have the historical background to seriously discuss such things. But one more thought:
The federal government, in theory, is beneficial in that it provides roads linking the states, a postal service, and other things that benefit each of the states individually and as a whole. The federal government also sets standards for equal rights and protections against discrimination (again, in theory). Conversely, the federal government, while they try, doesn't account very well for differences in state populations when it comes to implementing certain policies. Some things may work better for some states than others in certain cases, so a unified policy may be more detrimental to some states, but beneficial to others. Things like legalizing same-sex marriage, marijuana politics, allowing women the vote, abortion, and other equal rights and privacy concerns, on the other hand, shouldn't be left up to the states, because that is, in effect, allowing some states to discriminate or maintain discriminatory and even dangerous policies and practices for no reason other than to protect profit or dominance of the few in power.