Next meetup I'm buying you more beers. Your sarcasm meter needs lubrication."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."
Cliff Notes version - if a power isn't specifically given to the federal government in the Constitution, then it's reserved for the individual state to exercise (or not exercise, if they determine). It's a check to prevent a potentially unlimited power grab by the federal government.