Mike Rappaport argues that
(1)laws passed by a supermajority are superior to those passed by a majority because
(a) a supermajority protects minority interests, and
(b) greater support indicates significant public benefits;
(2)because the Constitution was passed by a supermajority,
(a) it should take precedence over other laws, and
(b) supports a "original meaning" interpretation of the Constitution because
(i) it enforces the original supermajoritarian view, and
(ii) the supermajoritarian process is superior to amendment by nine Justices.
I agree that legislation passed by a supermajority is generally superior to that passed by a simple majority, but there are many flaws in Mike's argument:
First, the Constitution was not actually passed by a supermajority: only white, male, landowners had a vote in early American society. Even a unanimous Constitution would not be passed by a majority. And that lack of a majority clearly had a large effect on the well being of particular minority groups.
Second, the Constitution was passed at one time 1793. If you consider the life of the State, the people who passed the Constitution are a very small minority. Any super majority at the time of formation is only valuable to the extent that they are an accurate reflection of the current and future interests and understanding of the People. I would imagine that over time there has been considerable drift on what an equitable consensus compromise establishing a nation-state should look like.
And this leads to my third point: supermajority requirements may unfairly benefit a minority that has an unfair advantage under the status quo. It was very difficult to get a supermajority to allow women to vote, give them equal control over their property, or control over their own bodies. Not only was the original Constitution not made by a supermajority, requiring a supermajority to change it locks in the power of a elite minority.
If your goal is to protect minority rights, the best way to do so is not by enshrining what white men in 1793 were the minority rights that they thought the Constitution would protect, but to allow an independent body to determine when laws are unfairly targeted at a minority group. And this is what has happened when our Supreme Court has protected interracial couples' right to marry, the ability of unmarried people to purchase contraception, and the right for the mentally retarded to not be zoned out of housing. The founders would probably not have thought this would have been the result of an equal protection clause.
And this, of course, leads to the fourth point: the original meaning of the Constitution was intended to be not entirely clear and subject to interpretation as the time required. (Ironically, it is the conservative strict constructionist orignalists who now seem most willing to ditch some of the most basic provisions of the Constitution -- like, say, judicial review -- on the ground that “the Constitution is not a suicide pact.” One might actually come to the conclusion that their preferred method of interpreting the Constitution, rather than being an objective way to constrain judicial policy-based decision is really simply a rational for reaching the policy-outcomes they prefer.) As Jack Balkin somewhat tangentially indicates and Justice Breyer argues in his book, you should not just look to what the original drafters or public thought how the Constitution would be applied to specific situations, but how they imagined and expected the Constitution would be interpreted and applied in the future. If the original drafters and public desired that the cultural values and economic, sociological, and scientific understandings of 1793 would be enshrined in the Constitution they could have stated so; they could have dictated how the Constitution would be interpreted. They did not. It is just as likely they thought that future generations would use the Constitution to protect democracy and minority rights as America went through cultural and scientific revolutions. At the time of passage, 1793, judges had must greater law making power than they do today. Almost all contract, tort and much criminal law was developed by judges. You might think that the founders expected and depended upon judges in the future shaping the law. I have gotten a little off topic. A bit on the ranting side, eh?
In conclusion, Mr. Rappaport's argument is thoroughly unpersuasive.