But I find it interesting that you see the Constitution as a tool that can be used against the interests of the states. Merely by leaving the Union, any state can use it to bludgeon the remaining state and there is nothing they can do. All the protections seem to apply to those leaving and not the ones remaining. The seceding states can repudiate any obligation, seize any property, take any action that harms the remaining states, and short of declaring war those states have no recourse whatsoever. I can't think that this is what the founding fathers had in mind.
I don't disagree, but I don't think the Founders envisioned a federal government that would be dependent on a single state (or a small group of states) for its survival. As I noted before, this appears to be one of the dangers of a massively bloated federal government. When the federal government takes on obligations that are beyond its means, this is one of the dangers that is run. I would suggest returning the federal government to its constitutional limits and many of the dangers of which you speak become considerably lessened--including, I suspect, any danger of secession.