I'll check out Popper but my point was that Levin is not the average radio jock, he is an attorney and long-time Constitutional scholar and always very thoughtful. As for my opinion of him, it's not like I'm in love with the guy, just that it's very hard to find someone on the radio or TV anymore who is smart and knows their stuff and is an actual professional and not just some entertainment personality.
His point is that if we do not explicitly amend the Constitution to say things like "Do X" or "do not do X" on 21st century language, that Progressives like Obama will continue to ignore the Constitution while claiming they are acting within their "interpretation of it."