"a few members of congress who are elected by the whole country and answer to the interests of the nation as a whole"

I strongly agree. I would go further. The idea of a regional representative might have made sense in an era before the Internet, before the telephone, before the telegram and even before railroads could ensure fast delivery of written mail, but it does it make sense now? Why not have a legislature where every member is chosen based on a vote of the whole nation? Some parliamentary democracies do this, and their policies do seem more focused on national interests, as opposed to a bunch of local interests. Also evaporates the problem of gerrymandering.