Michael, my point isn’t that these amendments are impossible to enforce. It’s that the most plausible enforcement mechanism (judicially ordered spending cuts and tax increases) is problematic. And there are reasons for thinking that the federal experience would be different, and worse (e.g., the existence of large popular entitlements run by the federal government).
My question to you is: What would happen if we had a constitutional amendment saying that spending/GDP had to be no more than 0.18 and the growth of entitlements put the next year’s estimated ratio at 0.19? A bunch of congressmen react, presumably, by wanting to cut entitlements; others by wanting to cut other forms of spending; still others by wanting to waive the rule because we’re in some military conflict. What forces a decision to be made and signed into law? And if the political branches don’t make a decision, do we really want the courts to step in?