But the phrase "relative to GDP" says a lot. Does a massive increase in toxic chemicals or interstate air or highway travel justify a greater role of the federal government in those areas? If it does, that allows for greater growth in government than mere population growth would. If it doesn't, serious troubles might arise or resources may have to come from somewhere else to regulate growing industries.
If we can find a way to make do with less government, fine. If government really is the main problem in some areas, great. Get it out of those areas. But like most people, I'm sceptical of claims that we can have a wholesale rollback of the federal government's powers.
Two "Republican revolutions" didn't bring the long awaited rollback. For that reason, it's doubtful to me that it will ever happen.