Why States' Rights?

It has been my observation over the years that few people truly understand why "States' Rights" were first instituted. Once that is understood it becomes a crucial principle, as opposed to just a concept that feels good because we tend prefer more local control.
Remember first the government that our founders and citizens had fled was enormous, and centrally controlled. These were the days of "The sun never sets on the British empire". They had witnessed, and suffered under, the corruption that ensued.
That said, we need not look much further than the name of our nation to understand what they were attempting to accomplish. The definition of the word "state" at that time was a sovereign government body. Noah Webster's 1828 edition defines it "A political body, or body politic; the whole body of people united under one government, whatever may be the form of the government." The premise under which this nation was formed, and named, is that we we would be individual sovereign governments forming a sort of Co-Op for specific purposes, such as common defense, commerce regulation, negotiating with foreign nations, etc. We were to be a group of sovereign states, united together for protective strength and position. (The electoral college is a fascinating tangent to this discussion. It creates a delicate balance in which it is the 'several states', not the people, that actually elect the president.) It's interesting to note that the term "States' rights" is actually a Civil War era creation, in response to the federal government expanding beyond its intended parameters. To our founders the concept was axiomatic.
The Constitution does not give rights to individuals. It gives very limited powers to the federal government with the presumption all others remained with the several states. The Bill of Rights was added later, only after intense debate. Proponents wanted to delineate some of our most important rights in order to protect them. Opponents feared that listing any rights would leave the impression that the list was all inclusive. The 10th amendment is the compromise between the two arguments.
Somewhere along the way most of our citizens lost track. Proposals made by elected federal officials began being debated on the merits of the idea, rather than on whether it is a legitimate federal function. As a result we now have, in practice, the type of government that our founders most feared. They foresaw that a powerful, centralized government would be a breeding ground for corruption.
I think time has proven them correct.